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Seubert J, Kellermann T, Boers F, Loughead J, Habel U. Neural correlates of olfactory-visual interactions in emotion processing. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)72006-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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27
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Weidner R, Boers F, Mathiak K, Dammers J, Fink G. The time course of the Müller-Lyer illusion as revealed by MEG. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)71296-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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28
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Dammers J, Schiek M, Boers F, Silex C, Zvyagintsev M, Pietrzyk U, Mathiak K. Integration of Amplitude and Phase Statistics for Complete Artifact Removal in Independent Components of Neuromagnetic Recordings. IEEE Trans Biomed Eng 2008; 55:2353-62. [DOI: 10.1109/tbme.2008.926677] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Heinzel A, Hautzel H, Poeppel T, Boers F, Beu M, Mueller HW. Neural correlates of subliminal and supraliminal letter processing—An event-related fMRI study. Conscious Cogn 2008; 17:685-99. [DOI: 10.1016/j.concog.2008.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 01/18/2008] [Accepted: 01/23/2008] [Indexed: 10/22/2022]
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Thoennessen H, Zvyagintsev M, Harke K, Boers F, Dammers J, Mathiak K, Norra C. Optimized mismatch negativity reflects deficits in schizophrenia patients in a combined EEG and MEG study. Eur Psychiatry 2008. [DOI: 10.1016/j.eurpsy.2008.01.852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Norra C, Thönneßen H, Zvyagintsev M, Harke K, Boers F, Dammers J, Mathiak K. Optimized Mismatch Negativity reflects correlates of deficient information processing in Schizophrenia: A combined EEG/MEG study. KLIN NEUROPHYSIOL 2008. [DOI: 10.1055/s-2008-1072962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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32
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Zvyagintsev M, Thönnessen H, Dammers J, Boers F, Mathiak K. An automatic procedure for the analysis of electric and magnetic mismatch negativity based on anatomical brain mapping. J Neurosci Methods 2007; 168:325-33. [PMID: 18093661 DOI: 10.1016/j.jneumeth.2007.10.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 10/22/2007] [Accepted: 10/24/2007] [Indexed: 10/22/2022]
Abstract
Data processing techniques in electroencephalography (EEG) and magnetoencephalography (MEG) need user interactions. However, particularly in clinical applications, fast and objective data processing is important. Here we present an observer-independent method for EEG and MEG analysis of mismatch negativity (MMN) that allows reliable estimation of source activity based on objective anatomical references. The procedure integrates several steps including artifact rejection, source estimation and statistical analysis. It enables the evaluation of source activity in a fully automatic and unsupervised manner. To test its feasibility we obtained EEG and MEG responses in an auditory oddball paradigm in 12 healthy volunteers. The automatized method of EEG and MEG data analysis estimated source activity. The automatically detected MMN was closely comparable with the results obtained by a user-controlled method based on the dipole fitting. The presented workflow can be performed easily, rapidly, and reliably. This development may open new fields in research and clinical applications of source-based EEG and MEG.
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Thoennessen H, Zvyagintsev M, Harke K, Boers F, Dammers J, Eulitz C, Mathiak K, Norra C. Preattentive auditory processing – A comparison between traditional and optimized paradigms in EEG and MEG. Clin Neurophysiol 2007. [DOI: 10.1016/j.clinph.2006.11.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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34
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Thönneßen H, Zvyagintsev M, Harke K, Boers F, Dammers J, Norra C, Mathiak K. Schizophrenia alters specific mismatch components in MEG and EEG. KLIN NEUROPHYSIOL 2007. [DOI: 10.1055/s-2007-976326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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35
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Dammers J, Mohlberg H, Boers F, Tass P, Amunts K, Mathiak K. A new toolbox for combining magnetoencephalographic source analysis and cytoarchitectonic probabilistic data for anatomical classification of dynamic brain activity. Neuroimage 2007; 34:1577-87. [PMID: 17187996 DOI: 10.1016/j.neuroimage.2006.09.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 09/05/2006] [Accepted: 09/26/2006] [Indexed: 10/23/2022] Open
Abstract
Size and location of activated cortical areas are often identified in relation to their surrounding macro-anatomical landmarks such as gyri and sulci. The sulcal pattern, however, is highly variable. In addition, many cortical areas are not linked to well defined landmarks, which in turn do not have a fixed relationship to functional and cytoarchitectonic boundaries. Therefore, it is difficult to unambiguously attribute localized neuronal activity to the corresponding cortical areas in the living human brain. Here we present new methods that are implemented in a toolbox for the objective anatomical identification of neuromagnetic activity with respect to cortical areas. The toolbox enables the platform independent integration of many types of source analysis obtained from magnetoencephalography (MEG) together with probabilistic cytoarchitectonic maps obtained in postmortem brains. The probability maps provide information about the relative frequency of a given cortical area being located at a given position in the brain. In the new software, the neuromagnetic data are analyzed with respect to cytoarchitectonic maps that have been transformed to the individual subject brain space. A number of measures define the degree of overlap between and distance from the activated areas and the corresponding cytoarchitectonic maps. The implemented algorithms enable the investigator to quantify how much of the reconstructed current density can be attributed to distinct cortical areas. Dynamic correspondence patterns between the millisecond-resolved MEG data and the static cytoarchitectonic maps are obtained. We show examples for auditory and visual activation patterns. However, size and location of the postmortem brain areas as well as the inverse method applied to the neuromagnetic data bias the anatomical classification. Therefore, the adaptation to the respective application and a combination of the objective quantities are discussed.
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Thoennessen H, Zvyagintsev M, Harke KC, Boers F, Dammers J, Eulitz C, Mathiak K, Norra C. Preattentive auditory processing – a comparison between traditional and optimized paradigms in EEG and MEG. KLIN NEUROPHYSIOL 2006. [DOI: 10.1055/s-2006-939303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Narayana KV, Martin A, L�cke B, Belmans M, Boers F, van Deynse D. Preparation, Solid-state Characteristics, and Catalytic Properties of Promoted Vanadium Phosphate Materials. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200400246] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Dammers J, Barnikol UB, Wuttich S, Boers F, Muren A, Mohlberg H, Amunts K, Zilles K, Tass PA. Combined MEG and Cytoarchitectonic Data Imaging. KLIN NEUROPHYSIOL 2004. [DOI: 10.1055/s-2004-831947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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39
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Boers F, Fieseler T, Muren A, Tass PA, Dammers J. Headshape Digitization using an Ultrasound 3D Acquisition System. KLIN NEUROPHYSIOL 2004. [DOI: 10.1055/s-2004-831934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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40
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Barnikol UB, Dammers J, Fieseler T, Boers F, Muren A, Wuttich S, Mohlberg H, Hesselmann G, Amunts K, Zilles K, Niedeggen M, Tass PA. Differential Activation of Visual Areas V1 and V5 by Pattern Reversal Stimulation – An MEG Study. KLIN NEUROPHYSIOL 2004. [DOI: 10.1055/s-2004-831922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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41
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Zafiris O, Kircheis G, Rood HA, Boers F, Häussinger D, Zilles K. Neural mechanism underlying impaired visual judgement in the dysmetabolic brain: an fMRI study. Neuroimage 2004; 22:541-52. [PMID: 15193582 DOI: 10.1016/j.neuroimage.2004.01.038] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2003] [Revised: 11/24/2003] [Accepted: 01/26/2004] [Indexed: 01/09/2023] Open
Abstract
An altered brain metabolism in the parietal and prefrontal regions of the cerebral cortex as well as cognitive alterations have been found in patients suffering from hepatic encephalopathy. The neural mechanisms underlying these metabolically induced cognitive alterations, however, are not known. Since patients with liver cirrhosis without clinically overt encephalopathy already show an impaired performance in a flicker light test, the aim of this study was to analyze the normal and pathologically impaired neural mechanisms of these patients using functional magnetic resonance imaging (fMRI). Nine subjects at the early stage of encephalopathy [nonmanifest hepatic encephalopathy (nmHE)] and ten controls underwent scanning, while they indicated the apparent transition from a steady light to the onset of a flicker light, that is, the critical flicker frequency (CFF). Judgement-related blood oxygenation level-dependent (BOLD) activation was decreased in nmHE compared to controls in the right inferior parietal cortex (IPL). Furthermore, the analysis of psychophysiologic interaction suggests impaired neural interaction in patients with nmHE, especially between the IPL and the parietooccipital cortex (Poc), the intraparietal sulcus, the anterior cingulate cortex (ACC), the right prefrontal cortex (PFC), the medial temporal lobe, and the extrastriate cortex V5. In contrast, nonmanifest patients revealed an enhanced coupling between IPL and the postcentral cortex. Our findings provide evidence of an early-impaired and compensatory neural mechanism during visual judgement already in the earliest stages of hepatic encephalopathy and suggest an aberrant coupling between cerebral regions in the dysmetabolic brain.
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Boers F. Expanding Learners' Vocabulary Through Metaphor Awareness: What Expansion, What Learners, What Vocabulary? STUDIES ON LANGUAGE ACQUISITION 2004. [DOI: 10.1515/9783110199857.211] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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43
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Boers F, Demecheleer M, Eyckmans J. 4. Etymological elaboration as a strategy for learning idioms. LANGUAGE LEARNING & LANGUAGE TEACHING 2004. [DOI: 10.1075/lllt.10.07boe] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Tass PA, Fieseler T, Dammers J, Dolan K, Morosan P, Majtanik M, Boers F, Muren A, Zilles K, Fink GR. Synchronization tomography: a method for three-dimensional localization of phase synchronized neuronal populations in the human brain using magnetoencephalography. PHYSICAL REVIEW LETTERS 2003; 90:088101. [PMID: 12633462 DOI: 10.1103/physrevlett.90.088101] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2002] [Indexed: 05/24/2023]
Abstract
We present a noninvasive technique which allows the anatomical localization of phase synchronized neuronal populations in the human brain with magnetoencephalography. We study phase synchronization between the reconstructed current source density (CSD) of different brain areas as well as between the CSD and muscular activity. We asked four subjects to tap their fingers in synchrony with a rhythmic tone, and to continue tapping at the same rate after the tone was switched off. The phase synchronization behavior of brain areas relevant for movement coordination, inner voice, and time estimation changes drastically when the transition to internal pacing occurs, while their averaged amplitudes remain unchanged. Information of this kind cannot be derived with standard neuroimaging techniques like functional magnetic resonance imaging or positron emission tomography.
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Dammers J, Fieseler T, Boers F, Muren A, Tass PA. Improving MEG's source localization accuracy by using continuous head motion detection. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)91447-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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46
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Tass PA, Fieseler T, Majtanik M, Dammers J, Morosan P, Boers F, Muren A, Zilles K, Fink GR. Synchronization tomography: synchronization analysis of MEG current density solutions in a tapping task. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)92580-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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47
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Tass PA, Volkmann J, Fieseler T, Majtanik M, Morosan P, Dammers J, Boers F, Muren A, Sturm V, Zilles K, Freund HJ. Synchronization tomography: Synchronization analysis of MEG current density solutions in patients with Parkinson's disease. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)92188-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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48
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Hautzel H, Mottaghy FM, Dammers J, Boers F, Tellmann L, Müller-Gärtner HW, Krause BJ. Temporal dynamics in working memory: A MEG study with PET-constrained dipole analysis. Neuroimage 2000. [DOI: 10.1016/s1053-8119(00)91340-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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49
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Boers F. The joy of counting metaphors: Relativity in the socio-economic domain. METAPHOR IN COGNITIVE LINGUISTICS 1999. [DOI: 10.1075/cilt.175.04boe] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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50
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Boers F, Lemiere G, Lepoivre JA, De Groot A, Dommisse R, De Bruyne T, Vlietinck AJ, Vanden Berghe DA. Synthesis and antiviral activity of 7-O-(omega-substituted)-alkyl-3-O-methylquercetin derivatives. DIE PHARMAZIE 1998; 53:512-7. [PMID: 9741060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
3',4'-Di-O-benzyl-3-O-methylquercetin (2), the precursor in the synthesis of an important antivirally active flavone 3-O-methylquercetin (1), was regioselectively alkylated at the 7-OH position by a series of 1,omega-dihaloalkanes and omega-bromoalkanols. Dimerization of the flavone had to be avoided by applying strict reaction conditions. Subsequent debenzylation was carried out by catalytic transfer hydrogenolysis, affording quantitatively the 7-O-(omega-haloalkyl)-3-O-methylquercetin (11-14) and 7-O-(omega-hydroxyalkyl)-3-O-methylquercetin derivatives (15, 16). All compounds were tested for their antiviral activity against poliomyelitis- and HIV-viruses.
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