Juliana A Knocikova | Institute of Chemical Technology Prague (original) (raw)

Papers by Juliana A Knocikova

Biomedical Signal Processing and Control, 2021

Major depressive disorder (MDD) is a severe psychiatric condition with increasing incidence. Diag... more Major depressive disorder (MDD) is a severe psychiatric condition with increasing incidence. Diagnostics and
development of novel therapeutic approaches are, however, hampered by the lack of reliable quantitative biomarkers enabling prediction of clinical outcomes. EEG is considered as an optimal source of such data due to its
broad availability, but traditional power spectral analysis was not designed for complex non-stationary EEG
recordings with nonlinear nature, and therefore often fails as a diagnostic and prognostic tool for MDD. As brain
activity is a highly complex, nonlinear and mostly irregular system, it can best be explained using the measures of
multiple time-frequency resolution, especially the wavelet analysis, chaos theory and methods of nonlinear
dynamics, such as fractal dimension or entropy. This non-conventional approach has proven to be highly sensitive to specific alterations of brain dynamics related to MDD. In this review, we consider the neurophysiological
correlates of MDD, describe the different analytical approaches, ranging from the traditional ones to the highly
innovative, and discuss their diagnostic relevance and practical utility. Our aim is to provide a current view of
the complex determinants related to brain activity under MDD, and emphasize the importance of interdisciplinary approaches to neurophysiological signal processing.

New York: ACM International Conference Proceeding, 2020

Tuberous Sclerosis Complex (TSC) is a severe pathological condition often accompanied by Autism S... more Tuberous Sclerosis Complex (TSC) is a severe pathological condition often accompanied by Autism Spectrum Disorder (ASD) and epilepsy. Recently, conclusions resulting from exploration of animal models suggested inhibition of mTOR to be a potential effective treatment. The EEG activity in Tsc2+/-(Eker) rat model has never been explored before. In this pilot study, we performed nonlinear EEG analysis to characterize its significant alterations resulting from treatment based on mTORi (inhibition of mammalian target of rapamycin), as well as from induction of developmental status epilepticus (DSE). Our results based of approximate entropy calculations confirmed that Everolimus (mTOR inhibitor) has a different influence on the regularity of EEG oscillations in wild-type and Tsc2+/-individuals. Moreover, we did not observe any alteration of EEG pattern complexity in adult rats with a history of DSE, and conclude that genotype (Tsc2+/-) and DSE state are probably influenced by different mechanisms of mTORi, with potential for clinical practice.

Respiratory Physiology & Neurobiology, 2008

The c-fos gene expression method was used to localize brainstem neurons functionally related to t... more The c-fos gene expression method was used to localize brainstem neurons functionally related to the tracheal-bronchial cough on 13 spontaneously breathing, pentobarbitone anesthetized cats. The level of Fos-like immunoreactivity (FLI) in 6 animals with repetitive coughs (170 ± 12) induced by mechanical stimulation of the tracheobronchial mucosa was compared to FLI in 7 control non-stimulated cats. Thirty-four nuclei were compared for the number of labeled cells. Enhanced cough FLI was found bilaterally at following brainstem structures, as compared to controls: In the medulla, FLI was increased in the medial, interstitial and ventrolateral subnuclei of the solitary tract (p < 0.02), in the retroambigual nucleus of the caudal medulla (p < 0.05), in the ambigual, paraambigual and retrofacial nuclei of the rostral medulla along with the lateral reticular nuclei, the ventrolateral reticular tegmental field (p < 0.05), and the raphe nuclei (p < 0.05). In pons, increased FLI was detected in the lateral parabrachial and Kölliker-Fuse nuclei (p < 0.01), in the posteroventral cochlear nuclei (p < 0.01), and the raphe midline (p < 0.05). Within the mesencephalon coughrelated FLI was enhanced at the rostral midline area (p < 0.05), but a decrease was found at its caudal part in the periaqueductal gray (p < 0.02). Results of this study suggest a large medullary -pontine -mesencephalic neuronal circuit involved in the control of the tracheal-bronchial cough in cats.

Biophysics and Medical Physics Computing, 2014

Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an... more Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an essential biophysical parameter for normal cellular activity. Cell volumes can be altered by osmotically active compounds and extracellular tonicity.
In this study, a simple mathematical model of osmotically induced cell swelling and shrinking is presented. Emphasis is given to water diffusion across the membrane. The mathematical description of the cellular behavior consists in a system of coupled ordinary differential equations. We compare experimental data of cell volume alterations driven by differences in osmotic pressure with mathematical simulations under hypotonic and hypertonic conditions. Implications for a future model are also discussed.

Keywords: eukaryotic cell, mathematical modeling, osmosis, volume alterations

Acta Veterinaria Brunensis, 2009

Despite high behavioural similarity, some differences in the central neural control of the cough ... more Despite high behavioural similarity, some differences in the central neural control of the cough and sneeze reflexes have been suggested. The main aim of our study was to analyze and compare characteristics of electromyographic (EMG) activities of the respiratory muscles during these two behaviours.
Data were taken from eight adult rabbits under pentobarbital anaesthesia. We compared diaphragm EMG activities in tracheobronchial cough, sneeze, and quiet breathing during inspiration. Electromyograms were read from the abdominal muscles during the expiratory phases of coughing and sneezing. Due to the non-stationary character of electromyographic signals, we used wavelet analysis to determine the time-frequency distribution of energy during the behaviours.
Inspiratory durations of all above mentioned behaviours were similar. The maximum inspiratory power occurred later in sneeze than during quiet inspiration (P < 0.05). The total inspiratory power during sneeze was higher compared to that in cough (P < 0.05) and quiet inspiration (P < 0.01). Lower frequencies contributed to this increase significantly more in sneeze compared to cough (less than 287.5 Hz, P < 0.05; 287.5 Hz up to 575 Hz, P < 0.01). We found similar energy distribution for coughing and quiet inspiration. Its maximum occurred at lower frequency in quiet inspiration compared to sneezing (P < 0.01). The abdominal burst during cough was longer than that in sneezing (P < 0.001). Our results support the concept that both cough and eupnoeic inspiration are generated by similar neuronal structures. A non-specific mechanism producing expiratory activity during tracheobronchial cough and sneeze is suggested.

Key words: defensive respiratory reflexes, neuronal control of breathing and airway reflexes, multiresolution analysis, EMG

Trends in biomedical engineering , 2009

Defensive airway reflexes represent an important participation in removal of irritants and noxiou... more Defensive airway reflexes represent an important participation in removal of irritants and noxious agents from the relevant parts of the airways. However, the central mechanisms being responsible for their generation are still not fully understood. In this study, electrical activity of the diaphragm was analyzed with regard to central inspiratory pattern generation in six adult anaesthetized rabbits.
Electromyographic features were compared in case of quiet and sneeze inspiration. Diaphragm investigation employed methods of wavelet transform enabling multiresolution signal analysis and a parameter approximate entropy characterizing signal complexity. Many differences in time – frequency energy distribution, especially for lower frequency bands, may suggest an involvement of specific neuronal structures (mechanisms) in sneezing responsible for its generation and/or shaping. Moreover, reduced complexity of the sneeze inspiratory activity could reflect an increased synchrony in function of appropriate neuronal groups compared to quiet breathing.

Keywords. Inspiratory pattern generation, EMG, rabbit,
wavelet transformation, approximate entropy.

Communications, 2010

Regulatory airway mechanisms were studied on the basis of phrenic nerve activity which was compar... more Regulatory airway mechanisms were studied on the basis of phrenic nerve activity which was compared during eupnea and aspiration reflex (AspR). Due to changing degrees of signal stationarity, discrete wavelet transformation enabling multiresolution analysis was performed, followed by calculation of wavelet energy and wavelet entropy parameters. The higher rate of wavelet energy was detected in lower frequency components during AspR in contrast to eupnea. Moreover, quiet inspiration is characterized by higher wavelet entropy comparing to the AspR, indicating the probability of its random character and varying degree of system disorder during transient between different respiratory responses.

Key words: biosignal processing, respiratory control, reflex, wavelet energy, entropy

JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 2008

Effects of kainic acid lesions in the medullary raphe midline on reflex expirations induced mecha... more Effects of kainic acid lesions in the medullary raphe midline on reflex expirations induced mechanically from the trachea were examined. Spontaneously breathing rabbits were anesthetized by ketamine and xylazine i.m., followed by pentobarbitone i.v. Excitatory neurotoxin kainic acid (2 mg/ml in artificial CSF, total volume of 55-100 nl) was pressure microinjected into the medullary midline, rostral to the obex (2 microinjections at 2 different depths). The lesion (mostly affected the obscurus and magnus raphe nuclei) reduced the number of reflex expirations by 80% and expiratory amplitudes of esophageal pressure, abdominal EMG moving averages, and abdominal EMG powers by 71%, 62%, and 57%, respectively (in all cases P<0.05). The duration of abdominal activity in post-lesion responses was not altered. Control microinjections of artificial CSF had no effect on the reflex responses. We conclude that in rabbits, the medullary raphe nuclei participate in the control of expiratory expulsions originating from the trachea.

Key words: expiration, cough, kainic acid, rabbit, raphe midline

JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 2008

Changes in the characteristics of the cough sound may refer to some specific pathological process... more Changes in the characteristics of the cough sound may refer to some specific pathological processes and their evolution. In this pilot study we analyzed voluntary cough sound properties in subjects with asthma bronchiale (AB) and chronic obstructive pulmonary disease (COPD) and discriminated them from the control cough sound in healthy subjects. The wavelet transform was used due to a nonstationarity of cough sound recordings. The duration of cough sound was longer during pathological conditions. The longest duration and the highest power of the cough sound were found in COPD. In AB patients, higher frequencies were detected compared with chronic bronchitis and the power of cough sound was shifted to a higher frequency range compared with control coughs. Cough sounds were classified
using discriminant analysis with a correct classification rate of about 85-90 %. The method of cough analysis enables an objective quantification of voluntary cough sound with a useful diagnostic and prognostic value.

Key words: asthma, chronic obstructive pulmonary disease, cough, sound analysis, wavelet transform

Computer Methods and Programs in Biomedicine, 2011

Aspiration reflex (AspR) represents a specific inspiratory motor behavior expressed by short, pow... more Aspiration reflex (AspR) represents a specific inspiratory motor behavior expressed by short, powerful inspiratory activity without subsequent active expiration and characterized by the ability to interrupt strong tonic inspiratory activity, as well as hypoxic apnea and several other functional disorders. Multiresolution analysis-based determination of spectral features arising during AspR has not yet been satisfactorily investigated.
The time–frequency energy distribution of phrenic nerve electrical activity was compared during the AspR, inspiratory phase of tracheobronchial cough and quiet inspiration.
Data obtained from 16 adult cats anesthetized with chloralose or pentobarbital were analyzed using a wavelet transformation, a sensitive method suitable for processing of the non-stationary respiratory output signal.
Phrenic nerve energy was accumulated within lower frequency bands in AspR bursts. In AspR, higher frequencies contributed less to the total power, when compared to cough inspiration. Moreover, AspR indicated a stable time–frequency energy distribution, regardless of which of the two types of anesthesia were used. Chloralose anesthesia induced a decrease of parameters in cough and quiet nspiration related to the quantity of energy.
The results indicate a specific method of information processing during generation of AspR, underlying its powerful ability to influence various severe functional disorders with potential implications for model experiments and clinical practice.

Keywords: Anesthesia, Aspiration reflex, Cat, Inspiration, Wavelet transformation

Respiratory Physiology & Neurobiology, 2008

The c-fos gene expression method was used to localize brainstem neurons functionally related to t... more The c-fos gene expression method was used to localize brainstem neurons functionally related to the tracheal-bronchial cough on 13 spontaneously breathing, pentobarbitone anesthetized cats. The level of Fos-like immunoreactivity (FLI) in 6 animals with repetitive coughs (170±12) induced by mechanical stimulation of the tracheobronchial mucosa was compared to FLI in 7 control nonstimulated cats. Thirty-four nuclei were compared for the number of labeled cells. Enhanced cough FLI was found bilaterally at following brainstem structures, as compared to controls: In the medulla, FLI was increased in the medial, interstitial and ventrolateral subnuclei of the solitary tract (p<0.02), in the retroambigual nucleus of the caudal medulla (p<0.05), in the ambigual, paraambigual and retrofacial nuclei of the rostral medulla along with the lateral reticular nuclei, the ventrolateral reticular tegmental field (p<0.05), and the raphe nuclei (p<0.05). In pons, increased FLI was detected in the lateral parabrachial and Kölliker-Fuse nuclei (p<0.01), in the posteroventral cochlear nuclei (p<0.01), and the raphe midline (p<0.05). Within the mesencephalon cough-related FLI was enhanced at the rostral midline area (p<0.05), but a decrease was found at its caudal part in the periaqueductal gray (p<0.02). Results of this study suggest a large medullary - pontine - mesencephalic neuronal circuit involved in the control of the tracheal-bronchial cough in cats.

Keywords: c-fos, brainstem, tracheal-bronchial cough, cat

Books by Juliana A Knocikova

Frontiers in Physiology, 2016

Despite a continuous effort in neurophysiological research during last decades, the understandin... more Despite a continuous effort in neurophysiological research during last decades, the
understanding of mechanisms regulating vital functions is still rather deficient. Investigating
the regulation of physiological processes has become a fully multidisciplinary task, highly
dependent on the usage of principles from mathematics, physics and computer science in
many aspects of view.
Due to changing degrees of neurophysiological data stationarity, the wavelet transformation is
often performed in imaging or time-frequency analysis. This multiresolution decomposition
results in a biosignal interpretation both in time and frequency domains. Therefore, it is
continuously adapted to the analyzed signal properties, and an optimal time–frequency
resolution may be reached. Wavelet analysis demonstrated attenuation of high frequency
components characterized by great oxygen demands in phrenic neurogram of newborn
mammals and even during some specific defence reflex behavior, suggesting dominance of
the basic respiratory rhythm generator in hypoxia/hypercapnia conditions.
Beside time - frequency energy distribution, qualitative changes of the neurophysiological
data could be demonstrated through nonlinear methods of analysis. Methods of nonlinear
dynamics are based on finding that random behavior can arise in deterministic nonlinear
systems with a few degrees of freedom. Many related parameters reflect system evolution in
time and, subsequently, reflect level of new signal pattern generation. They are often
understood as a rate of the system complexity. Particular parameters related to level of signal
entropy can describe dynamical behavior associated with different neurogram stages.
Decreasing of the entropy value detected in electroneurogram or electromyogram during
defence reflex behavior is reflecting low probability of system disorder. Thus, different
entropy measures show synchroncity of neural firing, level of diffusion energy over neurons
or a degree of synaptic activity.
In this research topic, innovative approaches in neurophysiological data modeling will be
introduced, and we welcome contributions ranging from original research reports, reviews,
technical or methodology articles. The topic will introduce novel biomedical, physical or
computational principles in understanding the complex processes of neurophysiological
regulations, including, but not limited to, time – frequency analysis, fuzzy logic, brain
mapping, artificial neuronal networks or nonlinear dynamics and the chaos theory.

Biomedical Signal Processing and Control, 2021

Major depressive disorder (MDD) is a severe psychiatric condition with increasing incidence. Diag... more Major depressive disorder (MDD) is a severe psychiatric condition with increasing incidence. Diagnostics and
development of novel therapeutic approaches are, however, hampered by the lack of reliable quantitative biomarkers enabling prediction of clinical outcomes. EEG is considered as an optimal source of such data due to its
broad availability, but traditional power spectral analysis was not designed for complex non-stationary EEG
recordings with nonlinear nature, and therefore often fails as a diagnostic and prognostic tool for MDD. As brain
activity is a highly complex, nonlinear and mostly irregular system, it can best be explained using the measures of
multiple time-frequency resolution, especially the wavelet analysis, chaos theory and methods of nonlinear
dynamics, such as fractal dimension or entropy. This non-conventional approach has proven to be highly sensitive to specific alterations of brain dynamics related to MDD. In this review, we consider the neurophysiological
correlates of MDD, describe the different analytical approaches, ranging from the traditional ones to the highly
innovative, and discuss their diagnostic relevance and practical utility. Our aim is to provide a current view of
the complex determinants related to brain activity under MDD, and emphasize the importance of interdisciplinary approaches to neurophysiological signal processing.

New York: ACM International Conference Proceeding, 2020

Tuberous Sclerosis Complex (TSC) is a severe pathological condition often accompanied by Autism S... more Tuberous Sclerosis Complex (TSC) is a severe pathological condition often accompanied by Autism Spectrum Disorder (ASD) and epilepsy. Recently, conclusions resulting from exploration of animal models suggested inhibition of mTOR to be a potential effective treatment. The EEG activity in Tsc2+/-(Eker) rat model has never been explored before. In this pilot study, we performed nonlinear EEG analysis to characterize its significant alterations resulting from treatment based on mTORi (inhibition of mammalian target of rapamycin), as well as from induction of developmental status epilepticus (DSE). Our results based of approximate entropy calculations confirmed that Everolimus (mTOR inhibitor) has a different influence on the regularity of EEG oscillations in wild-type and Tsc2+/-individuals. Moreover, we did not observe any alteration of EEG pattern complexity in adult rats with a history of DSE, and conclude that genotype (Tsc2+/-) and DSE state are probably influenced by different mechanisms of mTORi, with potential for clinical practice.

Respiratory Physiology & Neurobiology, 2008

The c-fos gene expression method was used to localize brainstem neurons functionally related to t... more The c-fos gene expression method was used to localize brainstem neurons functionally related to the tracheal-bronchial cough on 13 spontaneously breathing, pentobarbitone anesthetized cats. The level of Fos-like immunoreactivity (FLI) in 6 animals with repetitive coughs (170 ± 12) induced by mechanical stimulation of the tracheobronchial mucosa was compared to FLI in 7 control non-stimulated cats. Thirty-four nuclei were compared for the number of labeled cells. Enhanced cough FLI was found bilaterally at following brainstem structures, as compared to controls: In the medulla, FLI was increased in the medial, interstitial and ventrolateral subnuclei of the solitary tract (p < 0.02), in the retroambigual nucleus of the caudal medulla (p < 0.05), in the ambigual, paraambigual and retrofacial nuclei of the rostral medulla along with the lateral reticular nuclei, the ventrolateral reticular tegmental field (p < 0.05), and the raphe nuclei (p < 0.05). In pons, increased FLI was detected in the lateral parabrachial and Kölliker-Fuse nuclei (p < 0.01), in the posteroventral cochlear nuclei (p < 0.01), and the raphe midline (p < 0.05). Within the mesencephalon coughrelated FLI was enhanced at the rostral midline area (p < 0.05), but a decrease was found at its caudal part in the periaqueductal gray (p < 0.02). Results of this study suggest a large medullary -pontine -mesencephalic neuronal circuit involved in the control of the tracheal-bronchial cough in cats.

Biophysics and Medical Physics Computing, 2014

Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an... more Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an essential biophysical parameter for normal cellular activity. Cell volumes can be altered by osmotically active compounds and extracellular tonicity.
In this study, a simple mathematical model of osmotically induced cell swelling and shrinking is presented. Emphasis is given to water diffusion across the membrane. The mathematical description of the cellular behavior consists in a system of coupled ordinary differential equations. We compare experimental data of cell volume alterations driven by differences in osmotic pressure with mathematical simulations under hypotonic and hypertonic conditions. Implications for a future model are also discussed.

Keywords: eukaryotic cell, mathematical modeling, osmosis, volume alterations

Acta Veterinaria Brunensis, 2009

Despite high behavioural similarity, some differences in the central neural control of the cough ... more Despite high behavioural similarity, some differences in the central neural control of the cough and sneeze reflexes have been suggested. The main aim of our study was to analyze and compare characteristics of electromyographic (EMG) activities of the respiratory muscles during these two behaviours.
Data were taken from eight adult rabbits under pentobarbital anaesthesia. We compared diaphragm EMG activities in tracheobronchial cough, sneeze, and quiet breathing during inspiration. Electromyograms were read from the abdominal muscles during the expiratory phases of coughing and sneezing. Due to the non-stationary character of electromyographic signals, we used wavelet analysis to determine the time-frequency distribution of energy during the behaviours.
Inspiratory durations of all above mentioned behaviours were similar. The maximum inspiratory power occurred later in sneeze than during quiet inspiration (P < 0.05). The total inspiratory power during sneeze was higher compared to that in cough (P < 0.05) and quiet inspiration (P < 0.01). Lower frequencies contributed to this increase significantly more in sneeze compared to cough (less than 287.5 Hz, P < 0.05; 287.5 Hz up to 575 Hz, P < 0.01). We found similar energy distribution for coughing and quiet inspiration. Its maximum occurred at lower frequency in quiet inspiration compared to sneezing (P < 0.01). The abdominal burst during cough was longer than that in sneezing (P < 0.001). Our results support the concept that both cough and eupnoeic inspiration are generated by similar neuronal structures. A non-specific mechanism producing expiratory activity during tracheobronchial cough and sneeze is suggested.

Key words: defensive respiratory reflexes, neuronal control of breathing and airway reflexes, multiresolution analysis, EMG

Trends in biomedical engineering , 2009

Defensive airway reflexes represent an important participation in removal of irritants and noxiou... more Defensive airway reflexes represent an important participation in removal of irritants and noxious agents from the relevant parts of the airways. However, the central mechanisms being responsible for their generation are still not fully understood. In this study, electrical activity of the diaphragm was analyzed with regard to central inspiratory pattern generation in six adult anaesthetized rabbits.
Electromyographic features were compared in case of quiet and sneeze inspiration. Diaphragm investigation employed methods of wavelet transform enabling multiresolution signal analysis and a parameter approximate entropy characterizing signal complexity. Many differences in time – frequency energy distribution, especially for lower frequency bands, may suggest an involvement of specific neuronal structures (mechanisms) in sneezing responsible for its generation and/or shaping. Moreover, reduced complexity of the sneeze inspiratory activity could reflect an increased synchrony in function of appropriate neuronal groups compared to quiet breathing.

Keywords. Inspiratory pattern generation, EMG, rabbit,
wavelet transformation, approximate entropy.

Communications, 2010

Regulatory airway mechanisms were studied on the basis of phrenic nerve activity which was compar... more Regulatory airway mechanisms were studied on the basis of phrenic nerve activity which was compared during eupnea and aspiration reflex (AspR). Due to changing degrees of signal stationarity, discrete wavelet transformation enabling multiresolution analysis was performed, followed by calculation of wavelet energy and wavelet entropy parameters. The higher rate of wavelet energy was detected in lower frequency components during AspR in contrast to eupnea. Moreover, quiet inspiration is characterized by higher wavelet entropy comparing to the AspR, indicating the probability of its random character and varying degree of system disorder during transient between different respiratory responses.

Key words: biosignal processing, respiratory control, reflex, wavelet energy, entropy

JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 2008

Effects of kainic acid lesions in the medullary raphe midline on reflex expirations induced mecha... more Effects of kainic acid lesions in the medullary raphe midline on reflex expirations induced mechanically from the trachea were examined. Spontaneously breathing rabbits were anesthetized by ketamine and xylazine i.m., followed by pentobarbitone i.v. Excitatory neurotoxin kainic acid (2 mg/ml in artificial CSF, total volume of 55-100 nl) was pressure microinjected into the medullary midline, rostral to the obex (2 microinjections at 2 different depths). The lesion (mostly affected the obscurus and magnus raphe nuclei) reduced the number of reflex expirations by 80% and expiratory amplitudes of esophageal pressure, abdominal EMG moving averages, and abdominal EMG powers by 71%, 62%, and 57%, respectively (in all cases P<0.05). The duration of abdominal activity in post-lesion responses was not altered. Control microinjections of artificial CSF had no effect on the reflex responses. We conclude that in rabbits, the medullary raphe nuclei participate in the control of expiratory expulsions originating from the trachea.

Key words: expiration, cough, kainic acid, rabbit, raphe midline

JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 2008

Changes in the characteristics of the cough sound may refer to some specific pathological process... more Changes in the characteristics of the cough sound may refer to some specific pathological processes and their evolution. In this pilot study we analyzed voluntary cough sound properties in subjects with asthma bronchiale (AB) and chronic obstructive pulmonary disease (COPD) and discriminated them from the control cough sound in healthy subjects. The wavelet transform was used due to a nonstationarity of cough sound recordings. The duration of cough sound was longer during pathological conditions. The longest duration and the highest power of the cough sound were found in COPD. In AB patients, higher frequencies were detected compared with chronic bronchitis and the power of cough sound was shifted to a higher frequency range compared with control coughs. Cough sounds were classified
using discriminant analysis with a correct classification rate of about 85-90 %. The method of cough analysis enables an objective quantification of voluntary cough sound with a useful diagnostic and prognostic value.

Key words: asthma, chronic obstructive pulmonary disease, cough, sound analysis, wavelet transform

Computer Methods and Programs in Biomedicine, 2011

Aspiration reflex (AspR) represents a specific inspiratory motor behavior expressed by short, pow... more Aspiration reflex (AspR) represents a specific inspiratory motor behavior expressed by short, powerful inspiratory activity without subsequent active expiration and characterized by the ability to interrupt strong tonic inspiratory activity, as well as hypoxic apnea and several other functional disorders. Multiresolution analysis-based determination of spectral features arising during AspR has not yet been satisfactorily investigated.
The time–frequency energy distribution of phrenic nerve electrical activity was compared during the AspR, inspiratory phase of tracheobronchial cough and quiet inspiration.
Data obtained from 16 adult cats anesthetized with chloralose or pentobarbital were analyzed using a wavelet transformation, a sensitive method suitable for processing of the non-stationary respiratory output signal.
Phrenic nerve energy was accumulated within lower frequency bands in AspR bursts. In AspR, higher frequencies contributed less to the total power, when compared to cough inspiration. Moreover, AspR indicated a stable time–frequency energy distribution, regardless of which of the two types of anesthesia were used. Chloralose anesthesia induced a decrease of parameters in cough and quiet nspiration related to the quantity of energy.
The results indicate a specific method of information processing during generation of AspR, underlying its powerful ability to influence various severe functional disorders with potential implications for model experiments and clinical practice.

Keywords: Anesthesia, Aspiration reflex, Cat, Inspiration, Wavelet transformation

Respiratory Physiology & Neurobiology, 2008

The c-fos gene expression method was used to localize brainstem neurons functionally related to t... more The c-fos gene expression method was used to localize brainstem neurons functionally related to the tracheal-bronchial cough on 13 spontaneously breathing, pentobarbitone anesthetized cats. The level of Fos-like immunoreactivity (FLI) in 6 animals with repetitive coughs (170±12) induced by mechanical stimulation of the tracheobronchial mucosa was compared to FLI in 7 control nonstimulated cats. Thirty-four nuclei were compared for the number of labeled cells. Enhanced cough FLI was found bilaterally at following brainstem structures, as compared to controls: In the medulla, FLI was increased in the medial, interstitial and ventrolateral subnuclei of the solitary tract (p<0.02), in the retroambigual nucleus of the caudal medulla (p<0.05), in the ambigual, paraambigual and retrofacial nuclei of the rostral medulla along with the lateral reticular nuclei, the ventrolateral reticular tegmental field (p<0.05), and the raphe nuclei (p<0.05). In pons, increased FLI was detected in the lateral parabrachial and Kölliker-Fuse nuclei (p<0.01), in the posteroventral cochlear nuclei (p<0.01), and the raphe midline (p<0.05). Within the mesencephalon cough-related FLI was enhanced at the rostral midline area (p<0.05), but a decrease was found at its caudal part in the periaqueductal gray (p<0.02). Results of this study suggest a large medullary - pontine - mesencephalic neuronal circuit involved in the control of the tracheal-bronchial cough in cats.

Keywords: c-fos, brainstem, tracheal-bronchial cough, cat

Frontiers in Physiology, 2016

Despite a continuous effort in neurophysiological research during last decades, the understandin... more Despite a continuous effort in neurophysiological research during last decades, the
understanding of mechanisms regulating vital functions is still rather deficient. Investigating
the regulation of physiological processes has become a fully multidisciplinary task, highly
dependent on the usage of principles from mathematics, physics and computer science in
many aspects of view.
Due to changing degrees of neurophysiological data stationarity, the wavelet transformation is
often performed in imaging or time-frequency analysis. This multiresolution decomposition
results in a biosignal interpretation both in time and frequency domains. Therefore, it is
continuously adapted to the analyzed signal properties, and an optimal time–frequency
resolution may be reached. Wavelet analysis demonstrated attenuation of high frequency
components characterized by great oxygen demands in phrenic neurogram of newborn
mammals and even during some specific defence reflex behavior, suggesting dominance of
the basic respiratory rhythm generator in hypoxia/hypercapnia conditions.
Beside time - frequency energy distribution, qualitative changes of the neurophysiological
data could be demonstrated through nonlinear methods of analysis. Methods of nonlinear
dynamics are based on finding that random behavior can arise in deterministic nonlinear
systems with a few degrees of freedom. Many related parameters reflect system evolution in
time and, subsequently, reflect level of new signal pattern generation. They are often
understood as a rate of the system complexity. Particular parameters related to level of signal
entropy can describe dynamical behavior associated with different neurogram stages.
Decreasing of the entropy value detected in electroneurogram or electromyogram during
defence reflex behavior is reflecting low probability of system disorder. Thus, different
entropy measures show synchroncity of neural firing, level of diffusion energy over neurons
or a degree of synaptic activity.
In this research topic, innovative approaches in neurophysiological data modeling will be
introduced, and we welcome contributions ranging from original research reports, reviews,
technical or methodology articles. The topic will introduce novel biomedical, physical or
computational principles in understanding the complex processes of neurophysiological
regulations, including, but not limited to, time – frequency analysis, fuzzy logic, brain
mapping, artificial neuronal networks or nonlinear dynamics and the chaos theory.