Head

Dr. Burkhard Maess
Dr. Burkhard Maess
Group leader
Phone: +49 3425 8875-2526
Fax: +49 3425 8875-2511

Contact

Nancy Muschall
Assistant Methods and Development Units
Phone: +49 341 9940-2287
Fax: +49 341 9940-2448

MEG and Cortical Networks

MEG and EEG: Signal Analysis and Modelling

The work of "EEG and MEG: Signal analysis and modeling-group (short MEG-group) " is especially dedicated to the application of Magnetoencephalography (MEG) to neurocognitice research. On the other hand our interest is not be restricted applications of the MEG method, instead a combination of different views provided by other methods like funtional magnetic resonance (fMRI), electroencephalography (EEG), and as well as diffusion tensor imaging (DTI) will be of special advantage for our cognitive brain research. Efforts are made to exploit the potential of MEG to achieve a characterization of brain activity with reasonable spatial accuracy and, at the same time, with excellent temporal resolution. This trait distinguishes MEG from other measurements of brain activity, which either yield excellent spatial but poor temporal resolution (fMRI, PET) or good temporal, yet only limited spatial resolution (ERP). In order to extract the spatial information inherent in MEG recordings, elaborate models of the brain are used. In the MEG group, both commercially available and especially developed solutions are employed. The members of the MEG group conduct several own neurocognitive experiments. The topics tackled so far have been quite varied. They include early auditory processing, processing of syntax and semantics in spoken and written language, processing of prosodic information, as well as the perception of musical syntax and phrase structure. Such work is generally carried out in close co-operation with research teams at the main institute and elsewhere. The researchers of the MEG have a 306-channel whole-head magnetometer system at their disposal Firma Elekta Neuromag Oy(Vektorview, Elekta Neuromag Oy, Helsinki, Finnland ). The device is also equipped with a integrated 128-channel EEG system and auditory, visual and somatosensory stimulation are available. The group is housed in separate building in an electromagnetically quiet area, in order to ensure minimal disturbances of the measurements.

Science

Recent auditory oddball studies using syntactic stimuli report a syntactic effect on the mismatch negativity (sMMN) around 100–200 ms. For morphosyntactic violations, this sMMN effect has been localized in the left superior temporal cortex.

Localization of the syntactic mismatch negativity in the temporal cortex: An MEG study

Recent auditory oddball studies using syntactic stimuli report a syntactic effect on the mismatch negativity (sMMN) around 100–200 ms. For morphosyntactic violations, this sMMN effect has been localized in the left superior temporal cortex. [more]
The anatomical structures involved in distraction-related processing in the auditory domain were investigated using magnetoencephalography.

Primary motor area contribution to attentional reorienting after distraction

The anatomical structures involved in distraction-related processing in the auditory domain were investigated using magnetoencephalography. [more]
The localization of dipolar sources in the brain based on electroencephalography (EEG) or magnetoencephalography (MEG) data is a frequent problem in the neurosciences.

Reconstruction of multiple neuromagnetic sources using augmented evolution strategies-- a comparative study

The localization of dipolar sources in the brain based on electroencephalography (EEG) or magnetoencephalography (MEG) data is a frequent problem in the neurosciences. [more]
Natural stimuli are compiled of numerous features, which are cortically represented in dispersed structures. Synchronized oscillations in the Gamma-Band (>30 Hz; induced Gamma-Band Responses, iGBRs), are regarded ...

Sources of synchronized induced Gamma-Band responses during a simple object recognition task: A replication study in human MEG

Natural stimuli are compiled of numerous features, which are cortically represented in dispersed structures. Synchronized oscillations in the Gamma-Band (>30 Hz; induced Gamma-Band Responses, iGBRs), are regarded ... [more]
Based on results showing that the "deviant-minus-standard" estimate of the mismatch negativity (MMN) amplitude increases with increasing amounts of deviance, it has been suggested that the MMN amplitude ...

MMN or no MMN: No magnitude of deviance effect on the MMN amplitude.

Based on results showing that the "deviant-minus-standard" estimate of the mismatch negativity (MMN) amplitude increases with increasing amounts of deviance, it has been suggested that the MMN amplitude ... [more]
The current study used functional magnetic resonance imaging (fMRI) to investigate the neural basis of musical phrase boundary processing during the perception of music from native and non-native cultures.

Cross-cultural music phrase processing: An fMRI study

The current study used functional magnetic resonance imaging (fMRI) to investigate the neural basis of musical phrase boundary processing during the perception of music from native and non-native cultures. [more]
Changes in the pitch of repetitive sounds elicit the mismatch negativity (MMN) of the event-related brain potential (ERP). There exist two alternative accounts for this index of  ...

Localizing pre-attentive auditory memory-based comparison: Magnetic mismatch negativity to pitch change

Changes in the pitch of repetitive sounds elicit the mismatch negativity (MMN) of the event-related brain potential (ERP). There exist two alternative accounts for this index of  ... [more]
Mesh generation in finite-element- (FE) method-based electroencephalography (EEG) source analysis generally influences greatly the accuracy of the results. It is thus important to determine a meshing strategy ...

Geometry-Adapted Hexahedral Meshes Improve Accuracy of Finite-Element-Method-Based EEG Source Analysis

Mesh generation in finite-element- (FE) method-based electroencephalography (EEG) source analysis generally influences greatly the accuracy of the results. It is thus important to determine a meshing strategy ... [more]
In two experiments with event-related potentials (ERPs), we investigated the formation of auditory Gestalts. For this purpose, we used tone sequences of different structure. In the first experiment, we contrasted a rhythmic ...

Processing of Rhythmic and Melodic Gestalts—An ERP Study

In two experiments with event-related potentials (ERPs), we investigated the formation of auditory Gestalts. For this purpose, we used tone sequences of different structure. In the first experiment, we contrasted a rhythmic ... [more]
Sentence interpretation was examined with event-related brain potentials (ERPs). The ERPs were recorded while participants listened to French sentences containing a subject-modifying relative clause (SRC).

Neurodynamics of sentence interpretation: ERP evidence from French

Sentence interpretation was examined with event-related brain potentials (ERPs). The ERPs were recorded while participants listened to French sentences containing a subject-modifying relative clause (SRC). [more]
Cognitive control processes enable us to adjust our behavior to changing environmental demands. Although neuropsychological studies suggest that the critical cortical region for cognitive control is  ...

Who comes first? The role of the prefrontal and parietal cortex in cognitive control.

Cognitive control processes enable us to adjust our behavior to changing environmental demands. Although neuropsychological studies suggest that the critical cortical region for cognitive control is  ... [more]
When a particular speech sound is obliterated and replaced by a non-speech sound in continuous speech the listener may not notice any disturbance in speech or have difficulties in ...

Phonemic restoration in a sentence context: Evidence from early and late ERP effects

When a particular speech sound is obliterated and replaced by a non-speech sound in continuous speech the listener may not notice any disturbance in speech or have difficulties in ... [more]
Perception of a phoneme may occur even when the speech sound is missing (e.g., when an extraneous noise replaces the sound). This phenomenon, called phonemic restoration, has been observed to depend on the type of distortion.

Semantic retrieval of spoken words with an obliterated initial phoneme in a sentence context

Perception of a phoneme may occur even when the speech sound is missing (e.g., when an extraneous noise replaces the sound). This phenomenon, called phonemic restoration, has been observed to depend on the type of distortion. [more]
In this chapter, we report a number of studies applying magnetoencephalography (MEG) to the investigation of the modes of human communication. We seek to elucidate the ...

Human communication investigated with magnetoencephalography: Speech, music, and gestures

In this chapter, we report a number of studies applying magnetoencephalography (MEG) to the investigation of the modes of human communication. We seek to elucidate the ... [more]
Sensory feedback plays a major role in movement execution and motor learning, particularly in motor rehabilitation. Whilst elaborating therapeutic strategies, it is of interest to visualize the effect of a therapeutic intervention ...

Rapidly induced changes in neuromagnetic fields following repetitive hand movements

Sensory feedback plays a major role in movement execution and motor learning, particularly in motor rehabilitation. Whilst elaborating therapeutic strategies, it is of interest to visualize the effect of a therapeutic intervention ... [more]
We studied auditory sentence comprehension using magnetoencephalography while subjects listened to sentences whose correctness they had to judge subsequently.  ...

Localizing the distributed language network responsible for the N400 measured by MEG during auditory sentence processing

We studied auditory sentence comprehension using magnetoencephalography while subjects listened to sentences whose correctness they had to judge subsequently.  ... [more]
The loud acoustic noise produced by the magnetic resonance scanner is a major source of interference in auditory fMRI research. Whole-head magnetoencephalography (MEG) was used to investigate the interaction ...

Frequency specific impairment of automatic pitch change detection by fMRI acoustic noise: An MEG study

The loud acoustic noise produced by the magnetic resonance scanner is a major source of interference in auditory fMRI research. Whole-head magnetoencephalography (MEG) was used to investigate the interaction ... [more]
Electroencephalography (EEG) was used in a cross-cultural music study investigating phrase boundary perception. Chinese and German musicians performed a cultural categorization task under Chinese and Western music ...

The perception of musical phrase structure: A cross-cultural ERP study

Electroencephalography (EEG) was used in a cross-cultural music study investigating phrase boundary perception. Chinese and German musicians performed a cultural categorization task under Chinese and Western music ... [more]
A neural correlate for phrase boundary perception in music has recently been identified in musicians. It is called music closure positive shift ("music CPS") and has an equivalent in the perception of speech ("language CPS").

Effects of Musical Expertise and Boundary Markers on Phrase Perception in Music

A neural correlate for phrase boundary perception in music has recently been identified in musicians. It is called music closure positive shift ("music CPS") and has an equivalent in the perception of speech ("language CPS"). [more]
Enumerating the number of items in a set accurately and quickly is a basic mathematical skill. This ability is especially crucial in the more real-life situations, where relevant items have to be discriminated from irrelevant distracters. Although much work ...

Counting in everyday life: Discrimination and enumeration

Enumerating the number of items in a set accurately and quickly is a basic mathematical skill. This ability is especially crucial in the more real-life situations, where relevant items have to be discriminated from irrelevant distracters. Although much work ... [more]
To achieve a deeper understanding of the brain, scientists and clinicians use Electroencephalography (EEG) and Magnetoencephalography (MEG) inverse methods to reconstruct sources in the cortical sheet of the human brain. The influence of structural and electrical anisotropy ...

Influence of Anisotropic Conductivity on EEG/MEG Source Localization

To achieve a deeper understanding of the brain, scientists and clinicians use Electroencephalography (EEG) and Magnetoencephalography (MEG) inverse methods to reconstruct sources in the cortical sheet of the human brain. The influence of structural and electrical anisotropy ... [more]
Neither music nor spoken language form uniform auditory streams, rather, they are structured into phrases. For the perception of such structures, the detection of phrase boundaries is crucial. We discovered electroencephalography (EEG) and magnetoencephalography (MEG) correlates for the perception of phrase boundaries in music.

Perception of phrase structure in music

Neither music nor spoken language form uniform auditory streams, rather, they are structured into phrases. For the perception of such structures, the detection of phrase boundaries is crucial. We discovered electroencephalography (EEG) and magnetoencephalography (MEG) correlates for the perception of phrase boundaries in music. [more]
Hand signs with symbolic meaning can often be utilized more successfully than words to communicate an intention; however, the underlying brain mechanisms are undefined. The present study using magnetoencephalography (MEG) demonstrates ...

Cooperation of different neuronal systems during hand sign recognition

Hand signs with symbolic meaning can often be utilized more successfully than words to communicate an intention; however, the underlying brain mechanisms are undefined. The present study using magnetoencephalography (MEG) demonstrates ... [more]
We investigated the early ("preattentive") cortical processing of voice information, using the so-called "mismatch response". This brain potential allows inferences to be made about the ...

Dissociation of human and computer voices in the brain: evidence for a preattentive gestalt-like perception

We investigated the early ("preattentive") cortical processing of voice information, using the so-called "mismatch response". This brain potential allows inferences to be made about the ... [more]
The present study investigates the relationship of linguistic (phonetic) and extralinguistic (voice) information in preattentive auditory processing. We provide neurophysiological data, which show for the first time that ...

Early Parallel Processing of Auditory Word and Voice Information

The present study investigates the relationship of linguistic (phonetic) and extralinguistic (voice) information in preattentive auditory processing. We provide neurophysiological data, which show for the first time that ... [more]
The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, ...

Semantic Category Interference in Overt Picture Naming: Sharpening Current Density Localization by PCA

The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, ... [more]
The present experiment was designed to localize the neural substrates that process music-syntactic incongruities, using magnetoencephalography (MEG). Electrically, such processing has been proposed to be indicated by early right-anterior negativity (ERAN), ...

Musical syntax is processed in Broca's area: an MEG study

The present experiment was designed to localize the neural substrates that process music-syntactic incongruities, using magnetoencephalography (MEG). Electrically, such processing has been proposed to be indicated by early right-anterior negativity (ERAN), ... [more]
Time plays an important role in medical and neuropsychological diagnosis and research. In the field of Electro- and MagnetoEncephaloGraphy (EEG/MEG) source localization, a current distribution in the human brain is reconstructed ...

A parallel algebraic multigrid solver for finite element method based source localization in the human brain

Time plays an important role in medical and neuropsychological diagnosis and research. In the field of Electro- and MagnetoEncephaloGraphy (EEG/MEG) source localization, a current distribution in the human brain is reconstructed ... [more]
 
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