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De Pascalis V, Vecchio A, Cirillo G. Resting anxiety increases EEG delta–beta correlation: Relationships with the Reinforcement Sensitivity Theory Personality traits. PERSONALITY AND INDIVIDUAL DIFFERENCES 2020. [DOI: 10.1016/j.paid.2019.109796] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Horwitz A, Mortensen EL, Osler M, Fagerlund B, Lauritzen M, Benedek K. Passive Double-Sensory Evoked Coherence Correlates with Long-Term Memory Capacity. Front Hum Neurosci 2017; 11:598. [PMID: 29311868 PMCID: PMC5735981 DOI: 10.3389/fnhum.2017.00598] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 11/24/2017] [Indexed: 01/22/2023] Open
Abstract
HIGHLIGHTS Memory correlates with the difference between single and double-sensory evoked steady-state coherence in the gamma range (ΔC).The correlation is most pronounced for the anterior brain region (ΔCA ).The correlation is not driven by birth size, education, speed of processing, or intelligence.The sensitivity of ΔCA for detecting low memory capacity is 90%. Cerebral rhythmic activity and oscillations are important pathways of communication between cortical cell assemblies and may be key factors in memory. We asked whether memory performance is related to gamma coherence in a non-task sensory steady-state stimulation. We investigated 40 healthy males born in 1953 who were part of a Danish birth cohort study. Coherence was measured in the gamma range in response to a single-sensory visual stimulation (36 Hz) and a double-sensory combined audiovisual stimulation (auditive: 40 Hz; visual: 36 Hz). The individual difference in coherence (ΔC) between the bimodal and monomodal stimulation was calculated for each subject and used as the main explanatory variable. ΔC in total brain were significantly negatively correlated with long-term verbal recall. This correlation was pronounced for the anterior region. In addition, the correlation between ΔC and long-term memory was robust when controlling for working memory, as well as a wide range of potentially confounding factors, including intelligence, length of education, speed of processing, visual attention and executive function. Moreover, we found that the difference in anterior coherence (ΔCA ) is a better predictor of memory than power in multivariate models. The sensitivity of ΔCA for detecting low memory capacity is 92%. Finally, ΔCA was also associated with other types of memory: verbal learning, visual recognition, and spatial memory, and these additional correlations were also robust enough to control for a range of potentially confounding factors. Thus, the ΔC is a predictor of memory performance may be useful in cognitive neuropsychological testing.
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Affiliation(s)
- Anna Horwitz
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Rigshospitalet - Glostrup, Glostrup, Denmark
| | - Erik L Mortensen
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.,Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Merete Osler
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark.,Research Center for Prevention and Health, Rigshospitalet - Glostrup, Glostrup, Denmark
| | - Birgitte Fagerlund
- Center for Neuropsychiatric Schizophrenia Research, Psychiatric Center Glostrup, Glostrup, Denmark.,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Psychiatric Center Glostrup, Glostrup, Denmark
| | - Martin Lauritzen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Rigshospitalet - Glostrup, Glostrup, Denmark
| | - Krisztina Benedek
- Department of Clinical Neurophysiology, Rigshospitalet - Glostrup, Glostrup, Denmark
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The Characteristics and Relationships of Learning Abilities by Brain Preference and EEG According to Elementary School Students Academic Achievement Level. ADONGHAKOEJI 2015. [DOI: 10.5723/kjcs.2015.36.6.85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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4
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Impact of auditory distraction on user performance in a brain–computer interface driven by different mental tasks. Clin Neurophysiol 2011; 122:2003-9. [DOI: 10.1016/j.clinph.2011.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/22/2011] [Accepted: 03/24/2011] [Indexed: 11/18/2022]
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Reinhart RMG, Mathalon DH, Roach BJ, Ford JM. Relationships between pre-stimulus γ power and subsequent P300 and reaction time breakdown in schizophrenia. Int J Psychophysiol 2010; 79:16-24. [PMID: 20816708 DOI: 10.1016/j.ijpsycho.2010.08.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 08/19/2010] [Accepted: 08/19/2010] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Little is known about the relationship between gamma-band oscillations prior to the arrival of a target stimulus and subsequent sensory processing and response execution. Although schizophrenia has been associated with abnormalities in gamma-band oscillations, P300, and reaction time (RT), few studies have examined the possible correspondence between these three neurobiological and behavioral markers in schizophrenia. To characterize the relationship between preparatory processes, information processing, and subsequent behavioral performance in schizophrenia, the present study investigated the relationships between pre-stimulus gamma-band power, RT and P300 amplitude. METHODS EEG and behavioral data were collected from 18 schizophrenia patients and 21 healthy controls during a conventional auditory oddball task. RESULTS In controls, single-trial pre-stimulus gamma power was positively correlated with RT, and average P300 amplitude was positively correlated with average pre-stimulus gamma power. DISCUSSION We interpret these findings as evidence that gamma power enhancement reflects a state of greater pre-stimulus preparation resulting in fuller evaluation of the target stimulus and therefore slower RT, as proposed by Jokeit and Makeig (1994). Consistent with previous research, schizophrenia patients exhibited RT slowing and P300 amplitude reductions relative to controls. Importantly, neither RT nor P300 amplitude was related to pre-stimulus gamma power in schizophrenia, suggesting a breakdown in the preparatory brain state critical for stimulus processing and later motor execution. The present findings underscore the behavioral significance of gamma-band responses, and provide an additional link between gamma-band oscillations and information processing abnormalities in schizophrenia.
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Fallahpour K, Clarke SD, Goldberg E, Hermens DF, Falconer EM, Gordon E. Alterations in theta activity associated with novelty and routinization processing in ADHD. Clin Neurophysiol 2010; 121:1336-42. [DOI: 10.1016/j.clinph.2010.02.152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 02/02/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
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Güntekin B, Başar E. A new interpretation of P300 responses upon analysis of coherences. Cogn Neurodyn 2010; 4:107-18. [PMID: 21629584 PMCID: PMC2866369 DOI: 10.1007/s11571-010-9106-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 01/13/2010] [Accepted: 01/26/2010] [Indexed: 10/19/2022] Open
Abstract
Previous studies on cognitive dynamics showed that oscillatory responses of P300 are composed of mainly delta and theta responses. In the present study, for the first time, the long-distance intra-hemispheric event related coherence (auditory oddball paradigm) and evoked coherence (simple sound) were compared in order to evaluate the effects of cognitive tasks on the long-distance coherences. Seventeen healthy subjects (8 female, 9 male) were included in the study. The coherence was analyzed for delta (1-3.5 Hz), theta (4-7.5 Hz) and alpha (8-13 Hz) frequency ranges for (F(3)-P(3), F(4)-P(4), F(3)-T(7), F(4)-T(8), F(3)-O(1,) F(4)-O(2)) electrode pairs. The coherence to target responses were higher than the non-target and simple auditory response coherence. This difference is significant for the delta coherence for both hemispheres and for theta coherences over the left hemisphere. The highest coherences were recorded at fronto-temporal locations for all frequency bands (delta, theta, alpha). Furthermore, fronto-parietal coherences were higher than the fronto-occipital coherences for all frequency bands (delta, theta, alpha).These results show that the fronto-temporal and fronto-parietal connections are most relevant for the identification of the target signal. This analysis open the way for a new interpretation of dynamic localization results during cognitive tasks.
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Affiliation(s)
- Bahar Güntekin
- Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey
| | - Erol Başar
- Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kultur University, Istanbul, Turkey
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Herrmann CS, Fründ I, Lenz D. Human gamma-band activity: a review on cognitive and behavioral correlates and network models. Neurosci Biobehav Rev 2009; 34:981-92. [PMID: 19744515 DOI: 10.1016/j.neubiorev.2009.09.001] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 06/03/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
Abstract
Gamma-band oscillations (roughly 30-100 Hz) in human and animal EEG have received considerable attention in the past due to their correlations with cognitive processes. Here, we want to sketch how some of the higher cognitive functions can be explained by memory processes which are known to modulate gamma activity. Especially, the function of binding together the multiple features of a perceived object requires a comparison with contents stored in memory. In addition, we review recent findings about the actual behavioral relevance of human gamma-band activity. Interestingly, rather simple models of spiking neurons are not only able to generate oscillatory activity within the gamma-band range, but even show modulations of these oscillations in line with findings from human experiments.
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Affiliation(s)
- Christoph S Herrmann
- Department of Experimental Psychology, Carl-von-Ossietzky University, Oldenburg, Germany.
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Schadow J, Dettler N, Paramei GV, Lenz D, Fründ I, Sabel BA, Herrmann CS. Impairments of Gestalt perception in the intact hemifield of hemianopic patients are reflected in gamma-band EEG activity. Neuropsychologia 2008; 47:556-68. [PMID: 18996403 DOI: 10.1016/j.neuropsychologia.2008.10.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 09/26/2008] [Accepted: 10/03/2008] [Indexed: 10/21/2022]
Abstract
Gamma-band responses (GBRs) are associated with Gestalt perception processes. In the present EEG study, we investigated the effects of perceptual grouping on the visual GBR in the perimetrically intact visual field of patients with homonymous hemianopia and compared them to healthy participants. All observers were presented either random arrays of Gabor elements or arrays with an embedded circular arrangement. For the hemianopic patients, the circle was presented in their intact hemifield only. For controls, the hemifield for the circle presentation was counterbalanced across subjects. The participants were instructed to detect the circle by pressing a corresponding button. A wavelet transform based on Morlet wavelets was employed for the calculation of oscillatory GBRs. The early evoked GBR exhibited a larger amplitude and shorter latency for the healthy group compared to hemianopic patients and was associated with behavioral measures. The late total GBR between 200 and 400ms after stimulus onset was significantly increased for Gestalt-like patterns in healthy participants. This effect was not manifested in patients. The present findings indicate deficits in the early and late visual processing of Gestalt patterns even in the intact hemifield of hemianopic patients compared to healthy participants.
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Affiliation(s)
- Jeanette Schadow
- Department of Biological Psychology, Otto-von-Guericke-University of Magdeburg, Germany
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Rangaswamy M, Porjesz B. Uncovering genes for cognitive (dys)function and predisposition for alcoholism spectrum disorders: a review of human brain oscillations as effective endophenotypes. Brain Res 2008; 1235:153-71. [PMID: 18634760 DOI: 10.1016/j.brainres.2008.06.053] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 06/10/2008] [Indexed: 10/21/2022]
Abstract
Brain oscillations provide a rich source of potentially useful endophenotypes (intermediate phenotypes) for psychiatric genetics, as they represent important correlates of human information processing and are associated with fundamental processes from perception to cognition. These oscillations are highly heritable, are modulated by genes controlling neurotransmitters in the brain, and provide links to associative and integrative brain functions. These endophenotypes represent traits that are less complex and more proximal to gene function than either diagnostic labels or traditional cognitive measures, providing a powerful strategy in searching for genes in psychiatric disorders. These intermediate phenotypes identify both affected and unaffected members of an affected family, including offspring at risk, providing a more direct connection with underlying biological vulnerability. Our group has utilized heritable neurophysiological features (i.e., brain oscillations) as endophenotypes, making it possible to identify susceptibility genes that may be difficult to detect with diagnosis alone. We have discussed our findings of significant linkage and association between brain oscillations and genes in GABAergic, cholinergic and glutamatergic systems (GABRA2, CHRM2, and GRM8). We have also shown that some oscillatory indices from both resting and active cognitive states have revealed a common subset of genetic foci that are shared with the diagnosis of alcoholism and related disorders. Implications of our findings have been discussed in the context of physiological and pharmacological studies on receptor function. These findings underscore the utility of quantitative neurophysiological endophenotypes in the study of the genetics of brain function and the genetic diathesis underlying complex psychiatric disorders.
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Affiliation(s)
- Madhavi Rangaswamy
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Box 1203, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
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Abstract
The integration of multimodal stimuli has been regarded as important for the promotion of adaptive behavior. Although recent work has identified brain areas that respond to multimodal stimuli, the temporal features are not clear yet. Earlier event-related potential studies revealed crossmodal attention effects, but did not focus on mechanisms underlying crossmodal integration. Here, electroencephalography (EEG) activity in the gamma band was considered as a correlate of multimodal integration. Participants localized a tactile stimulus on their fingers while seeing visual stimuli on rubber hands with the same posture as their hands. EEG analyses using wavelet transform suggested that interelectrode phase synchrony in the gamma-band range (40-50 Hz) was related to behavioral indices of the intermodal illusion under consideration. The findings suggest a role of high-frequency oscillations in the integrative processing of stimuli across modalities.
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Affiliation(s)
- Noriaki Kanayama
- School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
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From perception to action: phase-locked gamma oscillations correlate with reaction times in a speeded response task. BMC Neurosci 2007; 8:27. [PMID: 17439642 PMCID: PMC1868743 DOI: 10.1186/1471-2202-8-27] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Accepted: 04/17/2007] [Indexed: 11/30/2022] Open
Abstract
Background Phase-locked gamma oscillations have so far mainly been described in relation to perceptual processes such as sensation, attention or memory matching. Due to its very short latency (≈90 ms) such oscillations are a plausible candidate for very rapid integration of sensory and motor processes. Results We measured EEG in 13 healthy participants in a speeded reaction task. Participants had to press a button as fast as possible whenever a visual stimulus was presented. The stimulus was always identical and did not have to be discriminated from other possible stimuli. In trials in which the participants showed a fast response, a slow negative potential over central electrodes starting approximately 800 ms before the response and highly phase-locked gamma oscillations over central and posterior electrodes between 90 and 140 ms after the stimulus were observed. In trials in which the participants showed a slow response, no slow negative potential was observed and phase-locked gamma oscillations were significantly reduced. Furthermore, for slow response trials the phase-locked gamma oscillations were significantly delayed with respect to fast response trials. Conclusion These results indicate the relevance of phase-locked gamma oscillations for very fast (not necessarily detailed) integration processes.
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Bucci P, Mucci A, Merlotti E, Volpe U, Galderisi S. Induced gamma activity and event-related coherence in schizophrenia. Clin EEG Neurosci 2007; 38:96-104. [PMID: 17515175 DOI: 10.1177/155005940703800212] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Evidence has been provided that high frequency oscillations within the gamma band reflect mechanisms of cortical integration. In the light of recently proposed pathophysiological models of schizophrenia, suggesting a disturbance of the functional connectivity within distributed neural networks, it has been hypothesized that abnormalities in the gamma band underlie perceptual and cognitive dysfunctions in patients with schizophrenia. In the present study we investigated evoked and induced 40-Hz gamma power as well as frontoparietal and frontotemporal event-related coherence in patients with deficit and nondeficit schizophrenia and in matched healthy controls. In patients, correlations between gamma oscillations and psychopathological dimensions were also investigated. A reduction of both induced gamma power and event-related coherence was observed in patients with nondeficit schizophrenia, but not in those with deficit schizophrenia. Our findings support the hypothesis that deficit and nondeficit schizophrenia represent separate disease entities, suggesting the presence of a poor integration of the neuronal activity within distributed neural network only in the subgroup of schizophrenic patients without primary and persistent negative symptoms. Associations between an excess of gamma oscillations and psychopathological dimensions were observed, suggesting that abnormal thoughts, behaviors and perceptions might be related to the formation of inappropriate neural connections.
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Affiliation(s)
- P Bucci
- Department of Psychiatry, University of Naples SUN, Naples, Italy.
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Padmanabhapillai A, Tang Y, Ranganathan M, Rangaswamy M, Jones KA, Chorlian DB, Kamarajan C, Stimus A, Kuperman S, Rohrbaugh J, O'Connor SJ, Bauer LO, Schuckit MA, Begleiter H, Porjesz B. Evoked gamma band response in male adolescent subjects at high risk for alcoholism during a visual oddball task. Int J Psychophysiol 2006; 62:262-71. [PMID: 16887227 DOI: 10.1016/j.ijpsycho.2006.05.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 05/02/2006] [Accepted: 05/04/2006] [Indexed: 11/30/2022]
Abstract
This study investigates early evoked gamma band activity in male adolescent subjects at high risk for alcoholism (HR; n=68) and normal controls (LR; n=27) during a visual oddball task. A time-frequency representation method was applied to EEG data in order to obtain stimulus related early evoked (phase-locked) gamma band activity (29-45 Hz) and was analyzed within a 0-150 ms time window range. Significant reduction of the early evoked gamma band response in the frontal and parietal regions during target stimulus processing was observed in HR subjects compared to LR subjects. Additionally, the HR group showed less differentiation between target and non-target stimuli in both frontal and parietal regions compared to the LR group, indicating difficulty in early stimulus processing, probably due to a dysfunctional frontoparietal attentional network. The results indicate that the deficient early evoked gamma band response may precede the development of alcoholism and could be a potential endophenotypic marker of alcoholism risk.
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Affiliation(s)
- Ajayan Padmanabhapillai
- Department of Psychiatry, State University of New York, Health Science Center at Brooklyn, SUNY, HSCB, Brooklyn, NY 11203, USA
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15
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Padmanabhapillai A, Porjesz B, Ranganathan M, Jones KA, Chorlian DB, Tang Y, Kamarajan C, Rangaswamy M, Stimus A, Begleiter H. Suppression of early evoked gamma band response in male alcoholics during a visual oddball task. Int J Psychophysiol 2006; 60:15-26. [PMID: 16019097 DOI: 10.1016/j.ijpsycho.2005.03.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Revised: 02/15/2005] [Accepted: 03/03/2005] [Indexed: 11/15/2022]
Abstract
We investigated the early evoked gamma frequency band activity in alcoholics (n=122) and normal controls (n=72) during a visual oddball task. A time-frequency representation method was applied to EEG data in order to obtain phase-locked gamma band activity (29-45 Hz) and was analyzed within a 0-150 ms time window range. Significant reduction of the gamma band response in the frontal region during target stimulus processing was observed in alcoholic compared to control subjects. In contrast, significantly higher gamma band response for the non-target stimulus was observed in alcoholics compared to controls. It is suggested that the reduction in early evoked frontal gamma band response to targets may be associated with frontal lobe dysfunction commonly observed in alcoholics. This perhaps can be characterized by a deficient top-down processing mechanism.
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Affiliation(s)
- Ajayan Padmanabhapillai
- Department of Psychiatry, Neurodynamics Laboratory, SUNY Health Science Center, Brooklyn, NY, USA
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Senkowski D, Talsma D, Herrmann CS, Woldorff MG. Multisensory processing and oscillatory gamma responses: effects of spatial selective attention. Exp Brain Res 2005; 166:411-26. [PMID: 16151775 DOI: 10.1007/s00221-005-2381-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Accepted: 10/22/2004] [Indexed: 10/25/2022]
Abstract
Here we describe an EEG study investigating the interactions between multisensory (audio-visual) integration and spatial attention, using oscillatory gamma-band responses (GBRs). The results include a comparison with previously reported event-related potential (ERP) findings from the same paradigm. Unisensory-auditory (A), unisensory-visual (V), and multisensory (AV) stimuli were presented to the left and right hemispaces while subjects attended to a designated side to detect deviant target stimuli in either sensory modality. For attended multisensory stimuli we observed larger evoked GBRs approximately 40-50 ms post-stimulus over medial-frontal brain areas compared with those same multisensory stimuli when unattended. Further analysis indicated that the integration effect and its attentional enhancement may be caused in part by a stimulus-triggered phase resetting of ongoing gamma-band responses. Interestingly, no such early interaction effects (<90 ms) could be found in the ERP waveforms, suggesting that oscillatory GBRs may be more sensitive than ERPs to these early latency attention effects. Moreover, no GBR attention effects could be found for the unisensory auditory or unisensory visual stimuli, suggesting that attention particularly affects the integrative processing of audiovisual stimuli at these early latencies.
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Affiliation(s)
- Daniel Senkowski
- Center for Cognitive Neuroscience, Duke University, Box 90999, Durham, NC 27708-0999, USA
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Mazaheri A, Picton TW. EEG spectral dynamics during discrimination of auditory and visual targets. ACTA ACUST UNITED AC 2005; 24:81-96. [PMID: 15922161 DOI: 10.1016/j.cogbrainres.2004.12.013] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Revised: 12/17/2004] [Accepted: 12/20/2004] [Indexed: 11/30/2022]
Abstract
This study measured the changes in the spectrum of the EEG (electroencephalogram) and in the event-related potentials (ERPs) as subjects detected an improbable target in a train of standard stimuli. The intent was to determine how these measurements are related, and to what extent the ERPs might represent phase-locked changes in EEG rhythms. The experimental manipulations were the stimulus modality (auditory or visual), the discriminability of the target, and the presence or absence of distraction. The ERPs showed sensory-evoked potentials that were specific to the modality and a target-evoked P300 wave that was later in the visual modality than in the auditory, and later and smaller when the discrimination was more difficult. The averaged EEG spectrograms showed that targets increased the frontal theta activity, decreased posterior and central alpha and beta activity, and decreased the central gamma activity. The scalp topography of the changes in the alpha and beta activity indicated a posterior desynchronization specific for the visual task and occurring with both targets and standards and a more widespread desynchronization for targets in either modality. Increased phase synchronization occurred during the event-related potentials, but modeling demonstrated that this can be seen when an evoked potential waveform is simply added to the background EEG. However, subtracting the spectrogram of the average ERP from the average spectrogram of the single trials indicated that phase-resetting of the background EEG rhythms can occur during the ERP. The idea that the ERPs and the EEG rhythms "share generators" can explain these findings.
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Affiliation(s)
- Ali Mazaheri
- Rotman Research Institute, Baycrest Centre for Geriatric Care, 3560 Bathurst Street, Toronto, Canada M6A 2E1
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De Pascalis V, Cacace I. Pain perception, obstructive imagery and phase-ordered gamma oscillations. Int J Psychophysiol 2005; 56:157-69. [PMID: 15804450 DOI: 10.1016/j.ijpsycho.2004.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Revised: 09/28/2004] [Accepted: 11/18/2004] [Indexed: 12/15/2022]
Abstract
The neural mechanisms underlying pain perception and anti-nociceptive effects of mental imagery are not well understood. Using a measure of phase-ordered beta and gamma EEG oscillations in response to painful electric stimulation, we recently found that somatosensory event-related phase-ordered gamma oscillations (38-42 Hz), elicited by the onset of painful stimuli over Cz scalp site, were linearly related to pain perception. In the present study, 38 subjects were engaged in a painful stimulus detection task using an oddball paradigm. This task was performed under a condition in which subjects were required simply to count the number of target stimuli (pain condition) and under another condition in which subjects were required to produce an obstructive mental imagery of painful stimulus perception (obstructive imagery). Only EEG responses to standard stimuli were analyzed in this study. Correlation analysis of sweeps for each individual revealed brief intervals of phase ordering of EEG patterns in the beta and gamma bands. The frequencies of interest were the beta1 (26-30 Hz), beta2 (30-34 Hz), gamma1 (34-38 Hz), gamma2 (38-42 Hz) and gamma3 (42-46 Hz) bands. Obstructive imagery treatment, compared to pain condition, significantly reduced pain perception. This reduction was paralleled by significant decreases of evoked phase-ordered gamma2 and gamma3 patterns over Cz scalp site. Phase-ordered oscillations at Cz scalp site, for both gamma2 and gamma3 bands, significantly predicted pain ratings during pain condition. Phase-ordered oscillation scores, obtained for these gamma bands over parietal and frontal scalp sites, resulted the best predictor of pain ratings during obstructive imagery. This study provides evidence for the role of gamma oscillations in the subjective experience of pain. Further, it has provided support for the view that pain reduction during obstructive mental imagery is the product of an inhibitory process involving frontal and parietal cortical regions.
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Tağluk ME, Cakmak ED, Karakaş S. Analysis of the time-varying energy of brain responses to an oddball paradigm using short-term smoothed Wigner–Ville distribution. J Neurosci Methods 2005; 143:197-208. [PMID: 15814152 DOI: 10.1016/j.jneumeth.2004.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2003] [Revised: 10/04/2004] [Accepted: 10/07/2004] [Indexed: 11/23/2022]
Abstract
Cognitive brain responses to external stimuli, as measured by event related potentials (ERPs), have been analyzed from a variety of perspectives to investigate brain dynamics. Here, the brain responses of healthy subjects to auditory oddball paradigms, standard and deviant stimuli, recorded on an Fz electrode site were studied using a short-term version of the smoothed Wigner-Ville distribution (STSW) method. A smoothing kernel was designed to preserve the auto energy of the signal with maximum time and frequency resolutions. Analysis was conducted mainly on the time-frequency distributions (TFDs) of sweeps recorded during successive trials including the TFD of averaged single sweeps as the evoked time-frequency (ETF) brain response and the average of TFDs of single sweeps as the time-frequency (TF) brain response. Also the power entropy and the phase angles of the signal at frequency f and time t locked to the stimulus onset were studied across single trials as the TF power-locked and the TF phase-locked brain responses, respectively. TFDs represented in this way demonstrated the ERP spectro-temporal characteristics from multiple perspectives. The time-varying energy of the individual components manifested interesting TF structures in the form of amplitude modulated (AM) and frequency modulated (FM) energy bursts. The TF power-locked and phase-locked brain responses provoked ERP energies in a manner modulated by cognitive functions, an observation requiring further investigation. These results may lead to a better understanding of integrative brain dynamics.
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Affiliation(s)
- M E Tağluk
- Department of Electric and Electronic Engineering, Inönü University, Malatya, Turkey.
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Gallinat J, Winterer G, Herrmann CS, Senkowski D. Reduced oscillatory gamma-band responses in unmedicated schizophrenic patients indicate impaired frontal network processing. Clin Neurophysiol 2004; 115:1863-74. [PMID: 15261865 DOI: 10.1016/j.clinph.2004.03.013] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2004] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Integration of sensory information by cortical network binding appears to be crucially involved in target detection. Studies in schizophrenia using functional and diffusion tensor neuroimaging, event-related potentials and EEG coherence indicate an impairment of cortical network coupling in this disorder. Previous electrophysiological investigations in animals and humans suggested that gamma activity (oscillations at around 40 Hz) is essential for cortical network binding. Studies in medicated schizophrenia provide evidence for a reduced gamma activity in the context of auditory stimulus processing. This is the first investigation of oscillatory activations in the gamma-band in an auditory oddball paradigm in unmedicated schizophrenic patients. METHODS EEG gamma-band responses (GBRs) of 15 drug-free schizophrenic patients and 15 age- and gender-matched healthy controls were compared. A wavelet transform based on Morlet wavelets was employed for the calculation of oscillatory GBRs. RESULTS In response to standard stimuli, early evoked GBRs (20-100 ms), which are supposed to reflect auditory cortex activation, did not show significant group differences. However, schizophrenic patients showed reduced evoked GBRs in a late latency range (220-350 ms), particularly after target stimuli. This deficit occurred over right frontal scalp regions. Furthermore, significant correlations were observed between oscillatory GBRs and clinical parameters in schizophrenic patients. CONCLUSIONS The results are consistent with a relative preserved stimulus processing in the auditory cortex as reflected by the early GBR. The reduced late GBR is compatible with an abnormal interaction within a frontal lobe network, as was postulated by previous neuroimaging studies. SIGNIFICANCE The present study provides evidence for disturbed processing within frontal cortical regions in unmedicated schizophrenic patients as indicated by reduced evoked EEG GBRs.
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Affiliation(s)
- Jürgen Gallinat
- Clinic for Psychiatry and Psychotherapy, Humboldt University, Berlin, Germany
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21
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Herrmann CS, Lenz D, Junge S, Busch NA, Maess B. Memory-matches evoke human gamma-responses. BMC Neurosci 2004; 5:13. [PMID: 15084225 PMCID: PMC419345 DOI: 10.1186/1471-2202-5-13] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Accepted: 04/13/2004] [Indexed: 11/15/2022] Open
Abstract
Background Human brain activity in the gamma frequency range has been shown to be a correlate of numerous cognitive functions like attention, perception and memory access. More specifically, gamma activity has been found to be enhanced when stimuli are stored in or match with short-term memory (STM). We tested the hypothesis that gamma activity is also evoked when stimuli match representations in long-term-memory (LTM). EEG was recorded from 13 subjects performing a choice reaction task. Visual stimuli were either known real-world objects with a memory representation or novel configurations never seen before. Results All stimuli evoked an early gamma response which was maximal over occipital electrodes. This evoked gamma activity was significantly larger for items that matched memory templates. Conclusions Therefore, we argue that gamma activity results from the feedback from memory into perception systems. This assumption seems to be true for STM as well as LTM.
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Affiliation(s)
- Christoph S Herrmann
- Otto-von-Guericke University, Dept. of Biological Psychology P.O. Box 4120, 39016 Magdeburg, Germany
- Max-Planck-Institute of Cognitive Neuroscience P.O. Box 500 355, 04303 Leipzig, Germany
| | - Daniel Lenz
- Otto-von-Guericke University, Dept. of Biological Psychology P.O. Box 4120, 39016 Magdeburg, Germany
| | - Stefanie Junge
- Otto-von-Guericke University, Dept. of Biological Psychology P.O. Box 4120, 39016 Magdeburg, Germany
| | - Niko A Busch
- Otto-von-Guericke University, Dept. of Biological Psychology P.O. Box 4120, 39016 Magdeburg, Germany
- Max-Planck-Institute of Cognitive Neuroscience P.O. Box 500 355, 04303 Leipzig, Germany
| | - Burkhard Maess
- Max-Planck-Institute of Cognitive Neuroscience P.O. Box 500 355, 04303 Leipzig, Germany
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Foucher JR, Otzenberger H, Gounot D. The BOLD response and the gamma oscillations respond differently than evoked potentials: an interleaved EEG-fMRI study. BMC Neurosci 2003; 4:22. [PMID: 14499000 PMCID: PMC222904 DOI: 10.1186/1471-2202-4-22] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2003] [Accepted: 09/19/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The integration of EEG and fMRI is attractive because of their complementary precision regarding time and space. But the relationship between the indirect hemodynamic fMRI signal and the more direct EEG signal is uncertain. Event-related EEG responses can be analyzed in two different ways, reflecting two different kinds of brain activity: evoked, i.e. phase-locked to the stimulus, such as evoked potentials, or induced, i.e. non phase-locked to the stimulus such as event-related oscillations. In order to determine which kind of EEG activity was more closely related with fMRI, EEG and fMRI signals were acquired together, while subjects were presented with two kinds of rare events intermingled with frequent distractors. Target events had to be signaled by pressing a button and Novel events had to be ignored. RESULTS Both Targets and Novels triggered a P300, of larger amplitude in the Novel condition. On the opposite, the fMRI BOLD response was stronger in the Target condition. EEG event-related oscillations in the gamma band (32-38 Hz) reacted in a way similar to the BOLD response. CONCLUSIONS The reasons for such opposite differential reactivity between oscillations / fMRI on the one hand, and evoked potentials on the other, are discussed in the paper. Those results provide further arguments for a closer relationship between fast oscillations and the BOLD signal, than between evoked potentials and the BOLD signal.
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Affiliation(s)
- Jack R Foucher
- Clinique Psychiatrique – INSERM U405, Hôpitaux Universitaires – BP 406 – 67091 Strasbourg Cedex – France
| | - Hélène Otzenberger
- UMR 7004 – CNRS/ULP – Institut de Physique Biologique, 4 rue Kirschleger – 67085 Strasbourg Cedex – France
| | - Daniel Gounot
- UMR 7004 – CNRS/ULP – Institut de Physique Biologique, 4 rue Kirschleger – 67085 Strasbourg Cedex – France
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Lee KH, Williams LM, Haig A, Gordon E. "Gamma (40 Hz) phase synchronicity" and symptom dimensions in schizophrenia. Cogn Neuropsychiatry 2003; 8:57-71. [PMID: 16571550 DOI: 10.1080/713752240] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The failure of integrative brain function is a fundamental characteristic of schizophrenia. Synchronous Gamma (40 Hz) activity, proposed as a candidate mechanism underlying the integration ("binding") of distributed brain activities, may provide a direct window into schizophrenic disintegration. METHODS 40 schizophrenia and 40 age/gender-matched control subjects participated in an auditory oddball paradigm. We examined both early (Gamma 1) and later Gamma (Gamma 2) phase synchrony to target stimuli. Factor analysis scores were used to examine the associations between Gamma synchrony and three syndromes (Psychomotor Poverty, Reality Distortion, and Disorganisation). RESULTS Multiple analyses of variance revealed an overall decrease in frontal and left hemisphere Gamma synchrony, but increased posterior Gamma 2 synchrony in schizophrenia compared to controls. Schizophrenia syndromes were differentiated by distinct patterns of Gamma disturbances: Psychomotor Poverty showed decreased left hemisphere synchrony; Reality Distortion was associated with increased right synchrony; Disorganisation showed a widespread enhancement with a delay in frontal Gamma synchrony. CONCLUSIONS These findings are consistent with previous evidence for left hemisphere and frontal disturbances in the schizophrenia group. However, the syndrome results point to more distinctive patterns of dysregulation in network integration: widespread and excessive in Disorganisation, localised and enhanced in Reality Distortion, versus localised and diminished in Psychomotor Poverty.
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Affiliation(s)
- Kwang-Hyuk Lee
- Westmead Hospital and University of Sydney, NSW, Australia.
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24
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Böttger D, Herrmann CS, von Cramon DY. Amplitude differences of evoked alpha and gamma oscillations in two different age groups. Int J Psychophysiol 2002; 45:245-51. [PMID: 12208531 DOI: 10.1016/s0167-8760(02)00031-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate whether the amplitude of gamma-band activity is influenced by the factor age. We examined alpha- and gamma-band EEG activity and event-related potentials (ERPs) of 12 subjects. Six subjects constituted the younger (mean age=36.6 years) and another six the older age group (mean age=47.6 years). Subjects performed a visual discrimination task which required a response to Kanizsa squares (targets) among Kanizsa-triangles and non-Kanizsa figures. The ERPs of the younger group revealed a significantly larger N 170 amplitude. The amplitudes of evoked alpha- and gamma-band activity were also found to be significantly higher in the younger group. We discuss the implications of these findings and possible reasons for a change of the oscillatory activity in the older age group.
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Affiliation(s)
- Diana Böttger
- Max-Planck Institute of Cognitive Neuroscience, Postfach 500 355, 04303, Leipzig, Germany
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25
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Sannita WG, Bandini F, Beelke M, De Carli F, Carozzo S, Gesino D, Mazzella L, Ogliastro C, Narici L. Time dynamics of stimulus- and event-related gamma band activity: contrast-VEPs and the visual P300 in man. Clin Neurophysiol 2001; 112:2241-9. [PMID: 11738194 DOI: 10.1016/s1388-2457(01)00700-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To investigate the time dynamics and phase relationship with the stimulus of the onset/offset visual evoked potentials (VEPs), P300 and gamma band oscillatory responses to visual (contrast) stimulation. Gamma band oscillatory activity mediates in sensory and cognitive operations, with a role in stimulus-related cortical synchronization, but is reportedly reduced in the time window of the P300 response. METHODS Ten healthy volunteers were studied. VEPs and P300 were obtained in a stimulus condition combining standard contrast stimulation and a visual odd-ball paradigm. Visual stimuli were gratings with a sinusoidal luminance profile (9.0 degrees central retina; 1.3 cycles/degree; 70% contrast) that were presented monocularly in onset/offset mode, with vertical orientation (frequent stimulus; 80%) or with a 15 degrees rotation to the right (infrequent, target stimulus). The total signal activity (temporal spectral evolution), the activity phase-locked to the stimulus onset (rectified integrated average), and the 'locking index' (ratio of the activity phase-locked to the stimulus to the total signal activity) were computed over time and across frequencies on the signals recorded at occipital (visual responses) and central locations (P300). RESULTS Oscillatory activity centered around approximately 20.0-35.0 Hz and phase-locked to the stimulus was recorded at occipital locations with time dynamics anticipating the conventional VEPs. Phase-locking was higher after frequent than in response to target stimuli and after the stimulus offset compared to onset, while the phase-locking of the VEP frequency components was higher after the stimulus onset. The low frequency components of the P300 recorded at Cz (below approximately 8.0-10.0 Hz) were almost totally phase-locked to the stimulus, while the gamma band activity at the P300 location did not vary over time in amplitude or phase-locking and was mostly non-locked to the target stimulus. CONCLUSIONS These observations add to the evidence of a role of the gamma band oscillatory responses (centered at approximately 20.0-35.0 Hz) in visual information processing and suggest that the increment in gamma band activity during cognitive operations also depends on task characteristics, vigilance or selective attention, and brain functional state. The visual P300 appears to reflect low frequency synchronization mechanisms.
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Affiliation(s)
- W G Sannita
- Neurophysiopathology, Department of Motor Science and Rehabilitation, University of Genoa, Genoa, Italy.
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Hamada T, Yamaguch M. Evoked and oscillatory neuromagnetic responses to sniffing odor in human subjects. Behav Brain Res 2001; 123:219-23. [PMID: 11399333 DOI: 10.1016/s0166-4328(01)00205-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We studied neuromagnetic responses to sniffing air and odor of lemon, lavender or soy sauce in two human subjects. Simple averaging of the data with respect to the onsets of the sniffs yielded odor-specific evoked responses over the right cortex with peak latency about 350 ms after the onsets. When the data were passed through band-pass filters centered around 48 Hz and of 320 ms in duration, rectified and then averaged, they yielded peaks, indicating transient oscillations, over the right frontal cortex with longer latency. We found such peaks in only 9 out of 26 experiments of sniffing odor, however.
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Affiliation(s)
- T Hamada
- National Institute of Advanced Science and Technology, MOL building, ONRI, 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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Lee KH, Williams LM, Haig A, Goldberg E, Gordon E. An integration of 40 Hz Gamma and phasic arousal: novelty and routinization processing in schizophrenia. Clin Neurophysiol 2001; 112:1499-507. [PMID: 11459690 DOI: 10.1016/s1388-2457(01)00584-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVES Frontal and lateralized schizophrenia disturbances were examined in terms of arousal-modulated changes in 40 Hz Gamma activity. METHODS Forty patients with schizophrenia and 40 age- and gender-matched controls were studied in a conventional auditory ERP oddball paradigm. We investigated sub-averaged Gamma activity based upon a simultaneous measure of electrodemal skin conductance response (phasic arousal) to differentiate novelty (large responses) from routinization (small or no responses). Both early Gamma (Gamma 1) and later induced Gamma (Gamma 2) activities were examined. RESULTS Patients with schizophrenia (compared with controls) had significantly reduced Gamma 1 amplitude in the right hemisphere for novelty processing and delayed Gamma 2 latency in the left hemisphere for both novelty and routinization. Overall, reduced Gamma 1 amplitude in patients with schizophrenia was also evident. CONCLUSIONS These findings indicate that the normal laterality of Gamma activity is specifically disturbed in schizophrenia in response to novel, but not routine (familiar) stimuli. The distinct pattern of findings suggests a dysregulation of activation across left and right hemispheres during initial attention and preparatory phases of information processing, in particular, in patients with schizophrenia.
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Affiliation(s)
- K H Lee
- The Brain Dynamics Centre, Westmead Hospital, NSW 2145, Westmead, Australia.
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Gurtubay IG, Alegre M, Labarga A, Malanda A, Iriarte J, Artieda J. Gamma band activity in an auditory oddball paradigm studied with the wavelet transform. Clin Neurophysiol 2001; 112:1219-28. [PMID: 11516733 DOI: 10.1016/s1388-2457(01)00557-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To examine the characteristics of evoked and induced gamma band oscillatory responses occurring during P300 development in an auditory oddball paradigm. METHODS A time-frequency analysis method was applied to an auditory oddball paradigm in 7 healthy subjects. This method combines a multiresolution wavelet algorithm for signal extraction and the Gabor transform to represent the temporal evolution of the selected frequency components. Phase-locked or evoked activity and also non-phase-locked activity were computed for both standard and target stimuli. RESULTS The gamma band frequency components differed between target and non-target stimuli processing. The study showed an early and mainly phase-locked oscillatory response appearing around 26--28 ms after both standard and target stimuli onset. This response showed a spectral peak around 44 Hz for both stimuli. A late oscillatory activity peaking at 37 Hz with a latency around 360 ms was observed appearing only for target stimuli. The latency of this late oscillatory activity had a high correlation (P=0.002) to the latency of the P300 wave. CONCLUSIONS EEG signal analysis with wavelet transform allows the identification of an early oscillatory cortical response in the gamma frequency range, as well as a late P300-related response.
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Affiliation(s)
- I G Gurtubay
- Clinical Neurophysiology Unit, Department of Neurology, Clínica Universitaria, Facultad de Medicina, Universidad de Navarra, Pamplona, Spain
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Slewa-Younan S, Gordon E, Williams L, Haig AR, Goldberg E. Sex differences, gamma activity and schizophrenia. Int J Neurosci 2001; 107:131-44. [PMID: 11328687 DOI: 10.3109/00207450109149762] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study explores the possibility that the more favourable clinical prognosis in females with schizophrenia may be associated with their greater network interconnectedness, which is possibly reflected in enhanced "Gamma" (40 Hz) electrical brain activity. An auditory "oddball" task was administered to 35 patients with schizophrenia and 35 age and sex matched controls (25 males and 10 females). Peak Gamma amplitude (from a time series of Gamma activity averaged for 40 target stimuli, as well as the immediately preceding 40 background tones) was examined across 19 sites. Peak Gamma activity occurred 250 to 450 ms in targets and 350 to 550 ms in backgrounds. Multiple within and between group MANOVAs were undertaken analysing both Peak Gamma amplitude (microvolts) and latency (milliseconds). Within-group, the control males showed a pattern of earlier Gamma latency in the right compared with the left hemisphere (F(1, 33)=3.70, p<.06), while control females exhibited delayed latency frontally compared with the posterior region (F(1, 33)=6.25, p<.04). This male lateralization finding and the anterior/posterior gradient in females is consistent with Goldberg's model. The patient group however, failed to show this male lateralized and female frontal-posterior pattern of Gamma activity, suggesting suboptimal network integration in the patient group, in both males and females.
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Affiliation(s)
- S Slewa-Younan
- Department of Psychological Medicine, University of Sydney, NSW, 2006, Australia.
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Elliott MA, Herrmann CS, Mecklinger A, Müller HJ. The loci of oscillatory visual-object priming: a combined electroencephalographic and reaction-time study. Int J Psychophysiol 2000; 38:225-41. [PMID: 11102664 DOI: 10.1016/s0167-8760(00)00167-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The detection of reaction-times (RTs) to a target Kanizsa-type square (an illusory square defined by the colinear arrangement of 90 degrees corner junctions) within a matrix of distractor junctions are expedited when the target display is preceded by a 40-Hz flickering display of premask crosses presented prior to, and at the locations subsequently occupied by the junctions of the target display. Priming effects were obtained when four crosses (which together matched the Gestalt arrangement of the target) were presented at the display locations subsequently occupied by the junctions forming the target Kanizsa square (Elliott and Müller, 1998, 2000). The present study was conducted with the aim of replicating the 40-Hz RT priming effects, while simultaneously recording the observers EEG in order to establish the presence and location of Gestalt priming in the brain. The statistical pattern obtained in the RT data corresponded well with previous studies and was matched by the pattern of target P300 latencies across bilateral central and posterior electrodes. Planned analyses focused upon the evoked 40-Hz activity that co-occurs with the P300, revealing a more specific pattern of 40-Hz priming over the visual cortex. A subsequent series of cross-correlational analyses examined the cortical distribution and timing of Gestalt-prime generation during and subsequent to premask-display presentation. Correlations were revealed between stimulus related 40-Hz activity over a range of cortical loci, including the right temporal lobe, which is considered important for figure coding. Taken together, these findings not only support the role of a distributed 40-Hz mechanism during Gestalt-figure priming, but also suggest that patterns of oscillatory brain activity may be directly influenced by, and interpretable in terms of equivalent temporal patterns of stimulus activity.
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Affiliation(s)
- M A Elliott
- Institut Für Allgemeine Psychologie, Universität Leipzig, Leipzig, Germany.
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Haig AR, Gordon E, De Pascalis V, Meares RA, Bahramali H, Harris A. Gamma activity in schizophrenia: evidence of impaired network binding? Clin Neurophysiol 2000; 111:1461-8. [PMID: 10904228 DOI: 10.1016/s1388-2457(00)00347-3] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Gamma ('40 Hz') rhythms may play a role in the integration of sensory processing activity. Impaired temporal integration may be a key feature of the associated disturbances in schizophrenia. This is the first study to examine the time course of Gamma activity induced in response to stimuli in this disorder. METHODS Gamma activity induced in response to task-relevant and irrelevant auditory oddball stimuli was examined in 35 medicated schizophrenics and 35 age- and gender-matched normal controls. We employed a moving Welch window with short time FFT to examine the time course of Gamma amplitude. The amplitude spectrum for each time point was de-trended to eliminate any contribution of broad spectrum activity (EEG or EMG) to Gamma amplitude. RESULTS For targets, schizophrenics showed a significant decrease in post-stimulus Gamma response amplitude in left hemisphere and frontal sites and an increase in right hemisphere and parieto-occipital sites (P<0.0009). The abnormalities correlated with PANSS general symptom scores. In the non-targets (at a different latency), schizophrenics showed a widespread Gamma decrease (P<0.0005). CONCLUSIONS The Gamma findings in non-targets may reflect an abnormality in appropriately processing irrelevant stimuli. This could result in defective processing of the context (integration) of relevant target information.
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Affiliation(s)
- A R Haig
- Cognitive Neuroscience Unit, Westmead Hospital, Sydney, Australia.
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Galbraith GC, Chae BC, Cooper JR, Gindi MM, Ho TN, Kim BS, Mankowski DA, Lunde SE. Brainstem frequency-following response and simple motor reaction time. Int J Psychophysiol 2000; 36:35-44. [PMID: 10700621 DOI: 10.1016/s0167-8760(99)00096-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Simple motor reaction times (RT) in humans show marked trial-to-trial variations. In the present study, a brief tone (400 Hz, 37.5 ms duration) that was the imperative stimulus in a RT paradigm evoked the brainstem frequency-following response (FFR). Horizontal and vertical montage FFRs were recorded to evaluate neural responses with putative origins in auditory nerve and central brainstem, respectively. The main question concerned the possible relationship between trial-to-trial variations in RT speed and FFR response properties. The results showed a reliable pattern in which fast RT trials yielded larger amplitudes (relative to slow trials) in earlier milliseconds of the FFR, and slow RT trials yielded relatively larger amplitudes in later milliseconds of the response. These results support the conclusion that early processing in the auditory brainstem is not automatic and invariant. Rather, short-latency evoked potentials appear to reflect trial-to-trial variations related to events far removed from the first synapse of sensory coding, perhaps depending upon cortically mediated influences such as cognition or attention.
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Affiliation(s)
- G C Galbraith
- University of California, Los Angeles, School of Medicine, Mental Retardation Research Center, Los Angeles, CA, USA.
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