TY  - JOUR
A1  - Beim Graben, Peter
A1  - Frisch, Stefan
A1  - Fink, A.
A1  - Saddy, Douglas
A1  - Kurths, Jürgen
T1  - Topographic voltage and coherence mapping of brain potentials by means of the symbolic resonance analysis
N2  - We apply the recently developed symbolic resonance analysis to electroencephalographic measurements of event- related brain potentials (ERPs) in a language processing experiment by using a three-symbol static encoding with varying thresholds for analyzing the ERP epochs, followed by a spin-flip transformation as a nonlinear filter. We compute an estimator of the signal-to-noise ratio (SNR) for the symbolic dynamics measuring the coherence of threshold-crossing events. Hence, we utilize the inherent noise of the EEG for sweeping the underlying ERP components beyond the encoding thresholds. Plotting the SNR computed within the time window of a particular ERP component (the N400) against the encoding thresholds, we find different resonance curves for the experimental conditions. The maximal differences of the SNR lead to the estimation of optimal encoding thresholds. We show that topographic brain maps of the optimal threshold voltages and of their associated coherence differences are able to dissociate the underlying physiological processes, while corresponding maps gained from the customary voltage averaging technique are unable to do so
Y1  - 2005
SN  - 1539-3755
ER  - 
TY  - JOUR
A1  - Beim Graben, Peter
A1  - Saddy, Douglas
A1  - Kurths, Jürgen
T1  - Untitled
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Beim Graben, Peter
A1  - Saddy, Douglas
A1  - Schlesewsky, Matthias
A1  - Kurths, Jürgen
T1  - Symbolic dynamics of event-related brain potentials
Y1  - 2000
ER  -