A5073190166- Neural dynamics and brain function
- EEG and Brain-Computer Interfaces
- Functional Brain Connectivity Studies
- Blind Source Separation Techniques
- Neuroscience and Neural Engineering
- Neural Networks and Applications
- Advanced MRI Techniques and Applications
- Neuroscience and Music Perception
- Visual perception and processing mechanisms
- Neural and Behavioral Psychology Studies
- Neuroscience and Neuropharmacology Research
- Spectroscopy and Chemometric Analyses
- Photoreceptor and optogenetics research
- Atomic and Subatomic Physics Research
- Complex Systems and Time Series Analysis
- Transcranial Magnetic Stimulation Studies
- Speech and Audio Processing
- Muscle activation and electromyography studies
- Multisensory perception and integration
- Bayesian Modeling and Causal Inference
- Mental Health Research Topics
- Sparse and Compressive Sensing Techniques
- Tactile and Sensory Interactions
- stochastic dynamics and bifurcation
- Advanced Neuroimaging Techniques and Applications
Universität Hamburg
2016-2025
University Medical Center Hamburg-Eppendorf
2016-2025
Institut de Neurophysiopathologie
2015
Fraunhofer Society
2005-2012
Pathologie Hamburg-West
2012
Fraunhofer Institute for Production Systems and Design Technology
2011
Technische Universität Berlin
2011
Fraunhofer Institute for Software and Systems Engineering
2010
Analysis Group (United States)
2010
Netherlands Leprosy Relief
2009
Abstract Objective: To address the problem of volume conduction and active reference electrodes in assessment functional connectivity, we propose a novel measure to quantify phase synchronization, lag index (PLI), compare its performance well‐known coherence (PC), imaginary component coherency (IC). Methods: The PLI is asymmetry distribution differences between two signals. PLI, PC, IC was examined (i) model 64 globally coupled oscillators, (ii) an EEG with absence seizure, (iii) data set 15...
We investigated whether functional brain networks are abnormally organized in Alzheimer's disease (AD). To this end, graph theoretical analysis was applied to matrices of connectivity beta band-filtered electroencephalography (EEG) channels, 15 Alzheimer patients and 13 control subjects. Correlations between all pairwise combinations EEG channels were determined with the synchronization likelihood. The resulting converted graphs by applying a threshold, cluster coefficients path lengths...
The equation for the magnetic lead field a given magnetoencephalography (MEG) channel is well known arbitrary frequencies omega but not directly applicable to MEG in quasi-static approximation. In this paper we derive an = 0 starting from very definition of instead using Helmholtz's reciprocity theorems. results are (a) transpose conductivity times divergence-free, and (b) differs one any other volume conductor by gradient scalar function. Consequently, piecewise homogeneous isotropic...
The BCI Competition IV stands in the tradition of prior Competitions that aim to provide high quality neuroscientific data for open access scientific community. As experienced already competitions not only scientists from narrow field compete, but scholars with a broad variety backgrounds and nationalities. They include specialists as well students. goals all have always been challenge respect novel paradigms complex data. We report on following challenges: (1) asynchronous data, (2)...
We propose a new measure (phase-slope index) to estimate the direction of information flux in multivariate time series. This (a) is insensitive mixtures independent sources, (b) gives meaningful results even if phase spectrum not linear, and (c) properly weights contributions from different frequencies. These properties are shown extended simulations contrasted Granger causality which yields highly significant false detections for sources. An application electroencephalography data...
Oscillatory neuronal synchronization between cortical areas has been suggested to constitute a flexible mechanism coordinate information flow in the human cerebral cortex. However, it remains unclear whether synchronized activity merely represents an epiphenomenon or is causally involved selective gating of information. Here, we combined bilateral high-density transcranial alternating current stimulation (HD-tACS) at 40 Hz with simultaneous electroencephalographic (EEG) recordings study...
Magnetoencephalographic and electroencephalographic evoked responses are primary real-time objective measures of cognitive perceptual processes in the human brain. Two mechanisms (additive activity phase reset) have been debated considered as only possible explanations for responses. Here we present theoretical empirical evidence a third mechanism contributing to generation Interestingly, this can be deduced entirely from characteristics spontaneous oscillations absence stimuli. We show that...
Background: Schizophrenia has long been suggested to represent a disorder with prominent neural dysconnectivity. Gamma-band oscillations are highly relevant in this context, due both their proposed involvement neuronal synchronization and association neurotransmitter systems for schizophrenia. Several task-related studies have confirmed reduced power of gamma-band schizophrenia, but it that these findings might not apply the resting state. The present study aimed investigate resting-state...
The ascending modulatory systems of the brain stem are powerful regulators global state. Disturbances these implicated in several major neuropsychiatric disorders. Yet, how interact with specific neural computations cerebral cortex to shape perception, cognition, and behavior remains poorly understood. Here, we probed into effect two such systems, catecholaminergic (dopaminergic noradrenergic) cholinergic on an important aspect cortical computation: its intrinsic variability. To this end,...
Catecholamines and acetylcholine have dissociable effects on large-scale cortical network activity behavior.
Artifacts in magnetoneurography data due to endogenous biological noise sources, like the cardiac signal, can be four orders of magnitude higher than signal interest. Therefore, it is important establish effective artifact reduction methods. We propose a blind source separation algorithm using only second-order temporal correlations for cleaning biomagnetic measurements evoked responses peripheral nervous system. The showed its efficiency by eliminating disturbances originating from and...
We propose a novel technique to assess functional brain connectivity in EEG/MEG signals. Our method, called Sparsely-Connected Sources Analysis (SCSA), can overcome the problem of volume conduction by modeling neural data innovatively with following ingredients: (a) EEG is assumed be linear mixture correlated sources multivariate autoregressive (MVAR) model, (b) demixing estimated jointly source MVAR parameters, (c) overfitting avoided using Group Lasso penalty. This approach allows extract...
A crucial aspect of cognitive control and learning is the ability to integrate feedback, that is, evaluate action outcomes their deviations from intended goals adjust behavior accordingly. However, how high-learners differ low-learners in relation feedback processing has not been characterized. Further, little known about underlying brain connectivity patterns during processing. This study aimed fill these gaps by analyzing electrical responses healthy adult human participants while they...
The integration of visual details into a holistic percept is essential for object recognition. This has been reported as key deficit in patients with autism spectrum disorders (ASDs). weak central coherence account posits an altered disposition to integrate features coherent whole ASD. Here, we test the hypothesis that such perceptual may be reflected neural across different cortical sites. We recorded magnetoencephalography from 20 adult human participants ASD and matched controls, who...