Stefan Kiebel

..It is shown that this procedure offers various advantages compared to existing conventional methods for the analysis of multisubject studies, in particular it is more sensitive to underlying activations...

..We illustrate this extension using synthetic data and empirical data from an oddball ERP experiment...

..We apply our procedure to real data and show that slice timings are important parameters. We conclude that, generally, one should use DCM with slice timing...

..Using synthetic and real data, we show that this approach furnishes accurate and robust conditional estimates of coupling among sources and their orientations...

..In this paper, we will motivate and describe the current DCM framework. Two examples show how the approach can be applied to M/EEG experiments...

..The framework provides predictions about, and principled constraints on, cortical structure-function relationships, which can be tested by manipulating the time-scales of sensory input...

..e., of unknown but constrained form). We describe the analysis procedures, the underlying theory and compare its performance to established techniques...

..We suggest that DCM and Bayesian model comparison provides a useful way to test hypotheses about distributed processing in the brain, using electromagnetic data...

..Another application is to hierarchical linear models, which are used for modeling multisubject data. To illustrate our approach, we apply it to some typical modeling scenarios in fMRI data analysis...

..By presenting anomalous stimuli, we find that the resulting recognition dynamics disclose inference at multiple time scales and are reminiscent of neuronal dynamics seen in the real brain...

..We illustrate the advantage of our Bayesian scheme, using a multi-subject EEG auditory study, where we compare competing models for the generation of the N100 component...

..This means the approach automatically selects either a sparse or a distributed model, depending on the data. The scheme is compared with conventional applications of Bayesian solutions to quantify the improvement in performance...

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..These examples show that category- or context-specific coupling among cortical regions can be assessed explicitly, within a mechanistic, biologically motivated inference framework...

..We then show that the brain has the necessary infrastructure to implement this inversion and present stimulations using synthetic birds that generate and recognise birdsongs...

..It is remarkable that distinct changes in intrinsic and extrinsic connections could be quantified so reliably and non-invasively using EEG...

..Our results provide empirical evidence for nonlinear coupling among distributed neuronal sources in the motor system and that these play an important role in modulating spectral responses under normal conditions...

..Our results point to a network account of speech recognition, in which information about the speech message and the speaker's vocal tract are combined to solve the difficult task of understanding speech from different speakers...

..Ilmoniemi, R.J., Levänen, S., Lin, F.H., May, P., Melcher, J., Stufflebeam, S., Tiitinen, H., Belliveau, J.W., 2004. Human posterior auditory cortex gates novel sounds to consciousness. Proc. Natl. Acad. Sci. U. S. A. 101, 6809-6814]...

..Further, VB allows for automatic selection of the order of the AR process. Results are shown on simulated data and on data from an event-related fMRI experiment...

..We then show that the brain has the necessary infrastructure to implement this inversion and illustrate this point using synthetic birds that can recognize and categorize birdsongs...

..The importance of implicit variance in neuronal states for neural-mass models of cortical dynamics is illustrated using both synthetic data and real EEG measurements of sensory evoked responses...

..In short, the free-energy formulation may provide an alternative perspective on the motor control that places it in an intimate relationship with perception...

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..The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain...

..Our data indicate that rapid learning regarding the moral status of others is expressed in altered neural activity within a system associated with social cognition...

..Finally, we illustrate how our approach can be used to quantify subjective beliefs and preferences that underlie inter-individual differences in behaviour...

..Reassuringly, we observe that the posterior is, for all practical purposes, insensitive of the choice of prior...

..Here, we describe the distributed spatial model and present a comparative evaluation with conventional equivalent current dipole (ECD) models of auditory processing, as measured with EEG...

..At the group level the FB-model supervened. We discuss these findings in terms of the validity and usefulness of DCM in characterising EEG/MEG data and its ability to model ERPs in a mechanistic fashion...

..These extensions are guided by the long-term goal of using dynamic system models for pharmacological and clinical applications, particularly with regard to synaptic plasticity...

..This is the theoretical cornerstone of most modern theories of perceptual inference and learning...

..We suggest that this optimization is based on speaker-specific audiovisual internal models, which are used to simulate a talking face...

..We establish the validity of parametric tests using synthetic and real data and compare its performance to established nonparametric procedures...

..Further work is necessary before firm conclusions may be drawn about the nature of this signal...

..Here, by analysing the time-frequency decompositions of single channel EEG data we show that RFT adjustments can be used in the analysis of electrophysiological data and illustrate the advantages of this method over existing approaches...

..The mean-field model presented here will form the basis of a dynamic causal model of observed electromagnetic signals in future work...

..We consider these mechanisms in the light of predictive coding and hierarchical inference in the brain...

..In a companion paper, we develop statistical models of ERPs in the time domain that follow from the heuristics established here and illustrate the approach using simulated and real data...

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