TY  - JOUR
AU  - Spasić, Slađana
AU  - Kalauzi, Aleksandar
AU  - Kesic, Srdjan
AU  - Obradović, Milica
AU  - Šaponjić, Jasna
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/460
AB  - We used spectral analysis and Higuchi fractal dimension (FD) to correlate the EEG spectral characteristics of the sensorimotor cortex, hippocampus, and pons with their corresponding EEG signal complexities in anesthetized rats. We have explored the quantitative relationship between the mean FDs and EEG wide range high frequency (8-50 Hz) activity during ketamine/xylazine versus nembutal anesthesia at surgical plane. Using FD we detected distinct inter-structure complexity pattern and uncovered for the first time that the polygraphically and behaviorally defined anesthetized state at surgical plane as equal during experiment in two anesthetic regimens, is not the same with respect to the degree of neuronal activity (degree of generalized neuronal inhibition achieved) at different brain levels. Using the correlation of certain brain structure EEG spectral characteristics with their corresponding FDs, and the surrogate data modeling, we determined what particular frequency band contributes to EEG complexities in ketamine/xylazine versus nembutal anesthesia. In this study we have shown that the quantitative relationship between higher frequency EEG amplitude and EEG complexity is the best-modeled by surrogate data as a 3rd order polynomial. On the base of our EEG amplitude/EEG complexity relationship model, and the evidenced spectral differences in ketamine versus nembutal anesthesia we have proved that higher amplitudes of sigma, beta, and gamma frequency in ketamine anesthesia yields to higher FDs.
PB  - Academic Press Ltd- Elsevier Science Ltd, London
T2  - Journal of Theoretical Biology
T1  - Surrogate data modeling the relationship between high frequency amplitudes and Higuchi fractal dimension of EEG signals in anesthetized rats
EP  - 166
SP  - 160
VL  - 289
DO  - 10.1016/j.jtbi.2011.08.037
ER  - 

@article{
author = "Spasić, Slađana and Kalauzi, Aleksandar and Kesic, Srdjan and Obradović, Milica and Šaponjić, Jasna",
year = "2011",
abstract = "We used spectral analysis and Higuchi fractal dimension (FD) to correlate the EEG spectral characteristics of the sensorimotor cortex, hippocampus, and pons with their corresponding EEG signal complexities in anesthetized rats. We have explored the quantitative relationship between the mean FDs and EEG wide range high frequency (8-50 Hz) activity during ketamine/xylazine versus nembutal anesthesia at surgical plane. Using FD we detected distinct inter-structure complexity pattern and uncovered for the first time that the polygraphically and behaviorally defined anesthetized state at surgical plane as equal during experiment in two anesthetic regimens, is not the same with respect to the degree of neuronal activity (degree of generalized neuronal inhibition achieved) at different brain levels. Using the correlation of certain brain structure EEG spectral characteristics with their corresponding FDs, and the surrogate data modeling, we determined what particular frequency band contributes to EEG complexities in ketamine/xylazine versus nembutal anesthesia. In this study we have shown that the quantitative relationship between higher frequency EEG amplitude and EEG complexity is the best-modeled by surrogate data as a 3rd order polynomial. On the base of our EEG amplitude/EEG complexity relationship model, and the evidenced spectral differences in ketamine versus nembutal anesthesia we have proved that higher amplitudes of sigma, beta, and gamma frequency in ketamine anesthesia yields to higher FDs.",
publisher = "Academic Press Ltd- Elsevier Science Ltd, London",
journal = "Journal of Theoretical Biology",
title = "Surrogate data modeling the relationship between high frequency amplitudes and Higuchi fractal dimension of EEG signals in anesthetized rats",
pages = "166-160",
volume = "289",
doi = "10.1016/j.jtbi.2011.08.037"
}

Spasić, S., Kalauzi, A., Kesic, S., Obradović, M.,& Šaponjić, J.. (2011). Surrogate data modeling the relationship between high frequency amplitudes and Higuchi fractal dimension of EEG signals in anesthetized rats. in Journal of Theoretical Biology
Academic Press Ltd- Elsevier Science Ltd, London., 289, 160-166.
https://doi.org/10.1016/j.jtbi.2011.08.037

Spasić S, Kalauzi A, Kesic S, Obradović M, Šaponjić J. Surrogate data modeling the relationship between high frequency amplitudes and Higuchi fractal dimension of EEG signals in anesthetized rats. in Journal of Theoretical Biology. 2011;289:160-166.
doi:10.1016/j.jtbi.2011.08.037 .

Spasić, Slađana, Kalauzi, Aleksandar, Kesic, Srdjan, Obradović, Milica, Šaponjić, Jasna, "Surrogate data modeling the relationship between high frequency amplitudes and Higuchi fractal dimension of EEG signals in anesthetized rats" in Journal of Theoretical Biology, 289 (2011):160-166,
https://doi.org/10.1016/j.jtbi.2011.08.037 . .

TY  - JOUR
AU  - Spasić, Slađana
AU  - Kesic, Srdjan
AU  - Kalauzi, Aleksandar
AU  - Šaponjić, Jasna
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/443
AB  - The complexity, entropy and other non-linear measures of the electroencephalogram ( EEG), such as Higuchi fractal dimension (FD), have been recently proposed as the measures of anesthesia depth and sedation. We hypothesized that during unconciousness in rats induced by the general anesthetics with opposite mechanism of action, behaviorally and poligraphically controlled as appropriately achieved stable anesthesia, we can detect distinct inter-structure brain dynamic using mean FDs. We used the surrogate data test for nonlinearity in order to establish the existence of nonlinear dynamics, and to justify the use of FD as a nonlinear measure in the time series analysis. The surrogate data of predefined probability distribution and autocorrelation properties have been generated using the algorithm of statically transformed autoregressive process (STAP). FD then is applied to quantify EEG signal complexity at the cortical, hippocampal and pontine level during stable general anesthesia (ketamine/xylazine or nembutal anesthesia). Our study showed for the first time that global neuronal inhibition caused by different mechanisms of anesthetic action induced distinct brain inter- structure complexity gradient in Sprague Dawley rats. EEG signal complexities were higher at cortical and hippocampal level in ketamine/ xylazine vs. nembutal anesthesia, with the dominance of hippocampal complexity. In nembutal anesthesia the complexity dominance moved to pontine level, and ponto- hippocampocortical decreasing complexity gradient was established. This study has proved the Higuchi fractal dimension as a valuable tool for measuring the anesthesia induced inter- structure EEG complexity.
PB  - World Scientific Publ Co Pte Ltd, Singapore
T2  - Fractals-Complex Geometry Patterns and Scaling in Nature and Society
T1  - Different anesthesia in rat induces distinct inter-structure brain dynamic detected by higuchi fractal dimension
EP  - 123
IS  - 1
SP  - 113
VL  - 19
DO  - 10.1142/S0218348X1100521X
ER  - 

@article{
author = "Spasić, Slađana and Kesic, Srdjan and Kalauzi, Aleksandar and Šaponjić, Jasna",
year = "2011",
abstract = "The complexity, entropy and other non-linear measures of the electroencephalogram ( EEG), such as Higuchi fractal dimension (FD), have been recently proposed as the measures of anesthesia depth and sedation. We hypothesized that during unconciousness in rats induced by the general anesthetics with opposite mechanism of action, behaviorally and poligraphically controlled as appropriately achieved stable anesthesia, we can detect distinct inter-structure brain dynamic using mean FDs. We used the surrogate data test for nonlinearity in order to establish the existence of nonlinear dynamics, and to justify the use of FD as a nonlinear measure in the time series analysis. The surrogate data of predefined probability distribution and autocorrelation properties have been generated using the algorithm of statically transformed autoregressive process (STAP). FD then is applied to quantify EEG signal complexity at the cortical, hippocampal and pontine level during stable general anesthesia (ketamine/xylazine or nembutal anesthesia). Our study showed for the first time that global neuronal inhibition caused by different mechanisms of anesthetic action induced distinct brain inter- structure complexity gradient in Sprague Dawley rats. EEG signal complexities were higher at cortical and hippocampal level in ketamine/ xylazine vs. nembutal anesthesia, with the dominance of hippocampal complexity. In nembutal anesthesia the complexity dominance moved to pontine level, and ponto- hippocampocortical decreasing complexity gradient was established. This study has proved the Higuchi fractal dimension as a valuable tool for measuring the anesthesia induced inter- structure EEG complexity.",
publisher = "World Scientific Publ Co Pte Ltd, Singapore",
journal = "Fractals-Complex Geometry Patterns and Scaling in Nature and Society",
title = "Different anesthesia in rat induces distinct inter-structure brain dynamic detected by higuchi fractal dimension",
pages = "123-113",
number = "1",
volume = "19",
doi = "10.1142/S0218348X1100521X"
}

Spasić, S., Kesic, S., Kalauzi, A.,& Šaponjić, J.. (2011). Different anesthesia in rat induces distinct inter-structure brain dynamic detected by higuchi fractal dimension. in Fractals-Complex Geometry Patterns and Scaling in Nature and Society
World Scientific Publ Co Pte Ltd, Singapore., 19(1), 113-123.
https://doi.org/10.1142/S0218348X1100521X

Spasić S, Kesic S, Kalauzi A, Šaponjić J. Different anesthesia in rat induces distinct inter-structure brain dynamic detected by higuchi fractal dimension. in Fractals-Complex Geometry Patterns and Scaling in Nature and Society. 2011;19(1):113-123.
doi:10.1142/S0218348X1100521X .

Spasić, Slađana, Kesic, Srdjan, Kalauzi, Aleksandar, Šaponjić, Jasna, "Different anesthesia in rat induces distinct inter-structure brain dynamic detected by higuchi fractal dimension" in Fractals-Complex Geometry Patterns and Scaling in Nature and Society, 19, no. 1 (2011):113-123,
https://doi.org/10.1142/S0218348X1100521X . .