Chapter 7. Mechanisms of antinoceptive response of a sensory neuron

The seventh chapter is devoted to the determination of the mechanisms of changes in the dynamic complexity of the patterns of impulse activity of nociceptors. As a result of the study of the mechanisms of changes in the dynamic complexity of the patterns of impulse activity of nociceptive neurons when the antinociceptive response occurs, it was found that the change in this complexity is based on rearrangements in the temporal organization of patterns due to bifurcations of stationary states and limit cycles, leading to the appearance of two types of burst activity. The mechanism of correction of the damaging pain effect is based on the molecular mechanism of suppression of this activity associated with the modification of the activation gating structure of slow sodium NaV1.8 channels under the action of comenic acid, a drug substance of the non-opioid analgesic “Anoceptin”. The methodology for analyzing the considered molecular mechanism can be used in the search for new pharmacological targets for further research related to the development of innovative pharmacological strategies in the correction of pathological conditions.

Chapter 5. Mechanisms of changes in dynamic complexity of EEG patterns in case of heart rhythm disturbances

The fifth chapter descibes the wavelet and recurrence analysis of changes occurring in reactive EEG patterns in disorders of the functional state of the central nervous system associated with cardiac arrhythmias of varying severity. It has been shown that individuals with paroxysmal atrial fibrillation are characterized by a significant assimilation of the rhythm of the frequencies of both the alpha and theta ranges, which may be associated with the development of instability of neurodynamic processes as a result of the appearance of a pathological focus of excitation in the central nervous system. In contrast to this, the weak photic driving reaction of the frequencies of the alpha range observed in persons with a constant form of atrial fibrillation and the pronounced reaction of the frequencies of the theta range may indicate the predominance of inhibition processes in the nervous system of these patients due to chronic hypoxia of the brain.

Chapter 1. Research methods

The first chapter presents methods for analyzing nonstationary physiological signals. Among them are 1) the method of continuous wavelet analysis, which allows obtaining the local and integral distribution of the energy of the wavelet spectrum of the signal over frequencies in a certain time interval, as well as providing information on the cross-wavelet spectrum and wavelet coherence of two signals; 2) methods for assessing the multifractality of a signal by searching for the maxima of the wavelet transform modulus maxima and by analyzing fluctuations relative to the trend; 3) the method of recurrent analysis, which allows to identify the quantitative parameters of the evolution of the signal in time, 4) the method of bifurcation analysis, which allows finding the values of the system parameters at which a qualitative change in the solution of the system occurs, for example, a change in the mode of impulse activity of a neuron.

Chapter 2. Mechanisms of changes in dynamic complexity of EEG patterns in epileptic brain injury

The second chapter is devoted to elucidating the mechanisms underlying the changes in the dynamic complexity of EEG patterns in disorders of the functional state of the brain associated with epileptic injuries, and modeling the possibility of automatic detection of epileptic discharges based on a comparative study of changes in wavelet spectra and the degree of multifractality of EEG patterns in patients with partial symptomatic epilepsy before, during and after epileptic discharges, as well as when opening the eyes and during hyperventilation during periods of absence of epileptic discharges. Comparative analysis of changes in wavelet spectra and in degree of multifractality of EEG patterns in patients with partial symptomatic epilepsy before, during and after epileptic discharges, as well as during covering the eyes and with hyperventilation during periods of absence of epileptic discharges, proved that changes in the values of multifractal parameters and the maximum of the global energy of the EEG wavelet spectrum can be used to automatically distinguish between periods before, during and after an epileptic discharge. Using multifractal analysis, it was found that the mechanism of changes in the dynamic complexity of EEG patterns during the occurrence of epileptic discharges is based on an increase in the contribution of weak fluctuations of successive EEG values, leading to an increase in their correlation and a significant increase in the energy of the wavelet spectrum and the degree of multifractality of the pattern in the preictal period.

Chapter 3. Mechanisms of changes in dynamic complexity of EEG patterns underlying correction of psychogenic pain in anxiety-phobic states

The third chapter explains the mechanisms for correcting anxiety-phobic states. For this, the changes occurring in the EEG patterns during the presentation of a painful stimulus and in the process of eliminating the pain sensation using the psychorelaxation technique in healthy individuals are considered; and these changes are compared with changes in EEG patterns during patients’ feelings of psychogenic pain and during its removal using psycho-relaxation techniques. It has been shown that the mechanisms underlying the correction of psychogenic pain in anxiety-phobic states are associated with changes in the dynamics of successive EEG values and the degree of their multifractality. With successful correction in the process of psychorelaxation in persons with anxiety-phobic disorders, there is a transition to the values of multifractal parameters characteristic for healthy people.

Chapter 6. Mechanisms of changes in dynamic complexity of involuntary oscillations of the human hand with movement disorders

The sixth chapter examines the mechanisms of changes in the dynamic complexity of hand tremor with an increase in the degree of motor disorders. For this, multifractal and wavelet properties of involuntary oscillations that arise during the performance of certain motor tasks by a healthy person and a person with varying degrees of motor pathology are investigated. It was shown that clinical manifestations of pathological tremor correlate, firstly, with a significant increase in the global energy of the wavelet spectrum and, secondly, with a decrease in the width of the singularity spectrum. At the same time, an improvement in the functional state (a decrease in the amplitude of a pathological tremor) corresponds to a decrease in long-term correlations and an increase in the randomness of up-down patterns, which corresponds to a partial shift of the singularity spectrum into the range of values typical for a tremor of the hand of a healthy person. The mechanism for reducing the dynamic complexity of patterns of involuntary oscillations of the human hand with an increase in the degree of motor disorders is based on a decrease in the contribution of strong fluctuations, accompanied by the appearance of long-term correlations of sequential values of tremor. The considered features in changes in tremor patterns make it possible to quantify the degree of movement disorders and can be used to facilitate the differential diagnosis of the parkinsonian and essential tremor in complex clinical cases.

Chapter 4. Analysis of the ability of the brain to assimilate the rhythm set frequency for vascular pathology varying degrees of severity

The fourth chapter is devoted to the analysis of changes occurring in reactive EEG patterns in disorders of the functional state of the central nervous system associated with vascular pathology of the brain. The coefficients of photic driving and holding and the energy increase times gained in EEG patterns of patients with dyscirculatory encephalopathy differ significantly from the parameters determined for the healthy subjects. When studying the changes occurring in reactive EEG patterns under the influence of rhythmic photostimulation, it was shown that various disorders of the functional state of the nervous system arising in vascular pathology of the brain of varying severity (initial manifestations in the form of vegetative vascular dystonia, more pronounced manifestations as a result of hypertension and vertebrobasilar insufficiency), manifest themselves as features of the brain to respond in a certain way to a given rhythm. It was shown that a healthy person is characterized by the absence of a reaction to assimilate an external rhythm or an insignificance of this reaction, associated with the absence of an increase in the energy of the wavelet spectrum near the frequency of photostimulation, which reflects the predominance of internal synchronization of the neural structures of a healthy brain. With an increase in the instability of neurodynamic processes, leading to the involvement of a larger number of neural ensembles in the pathological process, the destruction of internal synchronization occurs, which explains the increase in the quantitative indicators of the rhythm assimilation reaction in persons with essential hypertension and with vertebral-basilar insufficiency.