Methods for parameter identification in oscillatory networks and application to cortical and thalamic 600Hz activity

Leistritz, Lutz; Suesse, Thomas; Haueisen, Jens; Hilgenfeld, Bernd; Witte, Herbert

doi:10.1016/j.jphysparis.2005.06.007

Cited by 4 publications

(1 citation statement)

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“…This allows an identification of the parameters by a stochastic optimization procedure according to Solis and Wets (1981). We preferred the application of a global optimizer in order to reduce effects caused by the local convergence of deterministic procedures for the parameter identification that are especially prominent in the processing of oscillatory signals (Leistritz et al 2006). …”

Section: Modeling and Model-related Analysis By Coupled Duffing Oscilmentioning

confidence: 99%

Analysis and modeling of time-variant amplitude–frequency couplings of and between oscillations of EEG bursts

et al. 2008

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Low-frequency (0.5-2.5 Hz) and individually defined high-frequency (7-11 or 8-12 Hz; 11-15 or 14-18 Hz) oscillatory components of the electroencephalogram (EEG) burst activity derived from thiopental-induced burst-suppression patterns (BSP) were investigated in seven sedated patients (17-26 years old) with severe head injury. The predominant high-frequency burst oscillations (>7 Hz) were detected for each patient by means of time-variant amplitude spectrum analysis. Thereafter, the instantaneous envelope (IE) and the instantaneous frequency (IF) were computed for these low- and high-frequency bands to quantify amplitude-frequency dependencies (envelope-envelope, envelope-frequency, and frequency-frequency correlations). Time-variant phase-locking, phase synchronization, and quadratic phase couplings are associated with the observed amplitude-frequency characteristics. Additionally, these time-variant analyses were carried out for modeled burst patterns. Coupled Duffing oscillators were adapted to each EEG burst and by means of these models data-based burst simulations were generated. Results are: (1) strong envelope-envelope correlations (IE courses) can be demonstrated; (2) it can be shown that a rise of the IE is associated with an increase of the IF (only for the frequency bands 0.5-2.5 and 7-11 or 8-12 Hz); (3) the rise characteristics of all individually averaged envelope-frequency courses (IE-IF) are strongly correlated; (4) for the 7-11 or 8-12 Hz oscillation these associations are weaker and the variation between the time courses of the patients is higher; (5) for both frequency ranges a quantitative amplitude-frequency dependency can be shown because higher IE peak maxima are accompanied by stronger IF changes; (6) the time range of significant phase-locking within the 7-11 or 8-12 Hz frequency bands and of the strongest quadratic phase couplings (between 0.5-2.5 and 7-11 or 8-12 Hz) is between 0 and 1,000 ms; (7) all phase coupling characteristics of the modeled bursts accord well with the corresponding characteristics of the measured EEG burst data. All amplitude-frequency dependencies and phase locking/coupling properties described here are known from and can be discussed using coupled Duffing oscillators which are characterized by autoresonance properties.

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Section: Modeling and Model-related Analysis By Coupled Duffing Oscilmentioning

confidence: 99%