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Investigation of coherence structure and EEG activity propagation during sleep

100%

Kaminski M. , Blinowska K. , Szelenberger W.

Acta Neurobiologiae Experimentalis

1995

tom 55

nr 3

213-219

Overnight sleep EEG recorded from 21 derivtions was studied for 7 subjects (4 normal and 3 depressive).The multichannel autoregressive model was fitted to all 21 channels simultaneously.Ordinary, multiple and partial coherencies and directed trransfer function were estimated for sleep stages and wakefulness.Ordinary coherencies give rather trivial information that coherence decreases with the distance.Partial coherencies reveales specific structure to a large repeatable for studied subjects.Study of directed transfer function made possible the identification of main centres from which EEG activity is spreading during sleep.An EEG analysis, based on treating signals as a realization of one process and on simultaneous (not pair-wise) evolution of time series, offers new possibilities in the investigation of synchronization and functonal relations in brains.

Inductors and age effects on microsomal electron transfer chain from rat liver

100%

Plewka A. , Kaminski M. , Plewka D.

Postępy Higieny i Medycyny Doświadczalnej

1994

tom 48

nr 5

631-644

In this paper we showed age effect on NADPH-cytochrome P-450 reductase activity, cytochrome b5 and NADH-cytochrome b reductase from rat liver.We discussed effect of some I, II, and III classes inductor also.Activity NADPH-cytochrom P-450 reductase softly decreased from 0.5-2-month of life, but in older groups gradually increased.In 28-month-old rats it was twice fold youngest.Phenobarbital and dexamethasone (without 28-month-old age rats) induced but ?-naphthoflavone inhibited activity of this reductase.Cytochrome b content softly decreased to 4-month of life.In older animals changed of this hemoprotein content were not observed.The examined inductors of monooxygenase system decreased cytochrome b level.NADH-cytochrome b5 reductase activity increased to 1-month of life, but in older group decreased.After 2-month changes of activity were very small only.Phenobarbital, ?-naphthoflavone and dexamothasone inhibited activity of this reductase.

Analysis of multichannel biomedical data

100%

Kaminski M. , Zygierewicz J. , Kus R. , Crone N.

nr 3

443-452

Nowadays, there is a common practice in biomedical research to perform multiple time series recordings. In the first part of this paper, basic information about analysis of such multichannel biomedical data is given. A short overview of important differences between single-channel, two-channel and multichannel data sets is presented and various coherence functions are reported. Causal relations between channels are investigated by means of the Directed Transfer Function (DTF) and its dynamic version, the Short-Time Directed Transfer Function (SDTF). The introduced formalism was used to analyze 12-channel human electrocorticogram (ECoG) records. Preliminary results of a study of causal dependence in beta and gamma frequency bands in two patients performing a motor task are reported. Specific characteristics in activity propagation consistent for both subjects for different rhythms were found.

Inductors and age modifications of rat liver cytochrome P-450

100%

Plewka A. , Plewka D. , Kaminski M.

nr 4

453-468

In this paper we showed age effect on hepatic level of cytochrome P-450.We discussed effects of inductors on this hemoproteine also.Cytochrome P-450 content increased to 1-month of life, but decreased to 4-month.In the oldest rats cytochrome P-450 increased again.Content of this hemoprotein was induced by phenobarbital and ?- naphthoflavone in all examined groups, especially strong in young animals.Induction effect of dexamethasone was observed in 4-20 month of life.d

Transmission of information during Continuous Attention Test

100%

Kus R. , Blinowska K. J. , Kaminski M. , Basinska-Starzycka A.

Acta Neurobiologiae Experimentalis

2008

tom 68

nr 1

103-112

The Short-Time Directed Transfer Function (SDTF) is an estimator based on a multivariate autoregressive model which has proved to be successful in ERP experiments, e.g. those connected with motor action and its imagination. The aim of this study is the evaluation of the performance of SDTF in the cognitive experiment. We have applied SDTF for the estimation of the pattern of EEG signal transmissions during a Continuous Attention Test (CAT). Time-frequency patterns of propagation were estimated for two experimental conditions. Statistical procedures based on thin-plate spline model were used for estimation of significant changes in respect to the reference epoch. The repeatability of the results for a subject and across the subjects were investigated. The effect of prolonged transmission in the gamma band from the prefrontal electrodes found in all subjects was explained by the active inhibition in the case when a subject had to sustain from performing the action.