DYNAMICS OF THE IMPULSE ACTIVITY OF NEURONS IN THE VENTRAL POSTEROLATERAL NUCLEUS (VPL) OF THE RAT’S THALAMUS IN RESPONSE TO SOMATOSENSOR CORE STIMULATION IN A PARKINSON’S DISEASE MODEL

Neurodegenerative diseases are going to increase as the life expectancy is getting longer. Most patients with neurodegenerative diseases (ND) complain of pain, the origin of which remains largely unknown and requires further research. One of the reasons why the topic of pain and PD is difficult to address is that it is sometimes tough to discern whether a particular pain is due to PD or not. Chronic pain is such a common symptom among the general population, and people with PD are not immune to common problems as well. However, there are aspects of PD that may exacerbate the pain experienced from a common problem. In addition, there are particular types of pain that may be unique to people with PD. There is a frequent and more intense onset of pain in Parkinson’s disease, as the most important non-motor symptom, with a violation of both the emotional measurement of pain and the subjective perception of its intensity. In addition, various types of pain have been described in PD, mainly neuropathic or nociceptive. The presence of pain symptoms is often not taken into account in the recommendations for treatment, leaving their management at the discretion of only doctors. Studies focusing on pain frequency in such disorders suggest a high prevalence of pain in selected populations from 40% to 86% in Parkinson’s disease (PD). The methods of pain assessment vary between studies so the type of pain has been rarely reported. However, a prevalent nonneuropathic origin of pain emerged for PD. The electrophysiological investigations on 8 rats Albino lines (230±30g.) has been conducted: intacts (5 animals) and on the rotenone model of Parkinson’s disease (PD) (3 animals) has been conducted. The extracellular recording of impulse activity 229 single neurons of ventral-posterolateral nucleus (nVPL) of thalamus on high frequency stimulation of second somatosensory cortex of the brain has been produced. Analyses of relative degree frequency intensity of depressor and excitatory effects, on the bases of diagrams of average frequency of impulses, presented as disk graphs in mentioned conditions following changes of tetanic depressor and excitatory reactions, accompanied by posttetanic depressor and potentiation has been revealed. On the model of PD in both sequences, in comparison with norm, reduction in the number of neurons, responded by inhibitory poststimulus reactions has been revealed. The prestimulus frequency of nVPL neurons impulse activity, preceding to both inhibitory and excitatory sequences, in comparison with, dramatically increased turned out to be. The poststimulus frequency of impulse activity on the model of PD, accompanied by inhibitory and excitatory sequences also significantly increased turned out to be. A significant shift of frequency of pre- and poststimulus activity in pathology is a consequence of the development of excitotoxicity, that is fraught with apoptosis and dead. In conclusion, on the model of PD the excitotoxicity revealed in neurons of nVPL, leading to neurodegenerative defeat of these important antinociceptive structures of thalamus, with origin of resistant chronic pain. Marked indicates the need of protective conservation of inhibitory effects and reduced of excessive excitatory.

Results of recording electrophysiological signals by nanosensors during tests on volunteers

Purpose The purpose of this paper is to analyze the results of recording electrophysiological signals by nanosensors during tests on volunteers using neutral questions and questions that cause excitement. Design/methodology/approach The nanosensor-based hardware and software complex (HSC) was used for simultaneous recording of electrocardiogram, electroencephalogram and galvanic skin response during tests on volunteers using neutral questions and questions that cause excitement. The recording was carried out in real time without averaging and filtering in the extended frequency range from 0 to 10,000 Hz, level of more than 1 µV and sampling frequency equal to 64 kHz. Findings For the first time, the following signals were recorded by nanosensors without filtering and averaging in the measuring channels: real-time micropotentials on an electrocardiogram with a duration of 0.2 ms and a level of 1 µV or more. Also, for the first time, changes in the shape and amplitude of the P wave, slow waves on the electroencephalography (EEG), high impulse activity of the EEG and impulse activity of short duration on the GSR were recorded in response to questions that cause excitement. Practical implications The obtained results will be used for high-resolution equipment to develop additional measuring channels in existing types of equipment for psychophysiological studies. Originality/value For the first time, new data undistorted by filters was obtained on the amplitude and time parameters of electrophysiological signals in the frequency range from 0 to 10,000 Hz in response to questions that cause excitement, which was due to high sensitivity and noise immunity of nanosensors in comparison with existing electrodes for biopotential recording.

Electricity Works

This chapter focuses on the electrical activity of the brain. It first highlights Richard Caton’s demonstration of slow waves in the rabbit brain before an audience of physicians in Edinburgh in 1875. Then the chapter turns to the impact of Hans Berger’s discovery of similar slow waves in the human brain and of the advent of electroencephalography. The chapter finishes with the remarkable technical accomplishment of Mircea Steriade in being able to record from the same single neuron during periods of sleep and wakefulness, thereby showing the enormous range of impulse firing frequencies possible. From here, the chapter considers if it is possible that it is simply the intensity of the cortical discharge, with its thalamic underpinning, that determines whether or not impulse activity enters into consciousness.

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.

The central pattern generator underlying swimming in Dendronotus iris: a simple half-center network oscillator with a twist

The nudibranch mollusc, Dendronotus iris, swims by rhythmically flexing its body from left to right. We identified a bilaterally represented interneuron, Si3, that provides strong excitatory drive to the previously identified Si2, forming a half-center oscillator, which functions as the central pattern generator (CPG) underlying swimming. As with Si2, Si3 inhibited its contralateral counterpart and exhibited rhythmic bursts in left-right alternation during the swim motor pattern. Si3 burst almost synchronously with the contralateral Si2 and was coactive with the efferent impulse activity in the contralateral body wall nerve. Perturbation of bursting in either Si3 or Si2 by current injection halted or phase-shifted the swim motor pattern, suggesting that they are both critical CPG members. Neither Si2 nor Si3 exhibited endogenous bursting properties when activated alone; activation of all four neurons was necessary to initiate and maintain the swim motor pattern. Si3 made a strong excitatory synapse onto the contralateral Si2 to which it is also electrically coupled. When Si3 was firing tonically but not exhibiting bursting, artificial enhancement of the Si3-to-Si2 synapse using dynamic clamp caused all four neurons to burst. In contrast, negation of the Si3-to-Si2 synapse by dynamic clamp blocked ongoing swim motor patterns. Together, these results suggest that the Dendronotus swim CPG is organized as a “twisted” half-center oscillator in which each “half” is composed of two excitatory-coupled neurons from both sides of the brain, each of which inhibits its contralateral counterpart. Consisting of only four neurons, this is perhaps the simplest known network oscillator for locomotion.

Changes in intracellular potentials and ionic currents of the mollusk and activity of Cl--channels under exposure to some inhibitory amino acids and new litium-containing compounds of them

The Changes of membrane rest potential (RP), action potential (AP), impulse activity (IA) as well as sodium, calcium and potassium ionic currents in neurons of isolated central nervous system of the Planorbarius corneus mollusk (pedal ganglia) under the extracellular action of inhibitory amino acids GABA, glycine and β-alanine and their litium-containing derivatives (LCD) in 0.1, 1 and 5 mM concentrations have been studied using a microelectrode technique. They induced the same dose-dependent and irreversible depolarization of neurons on 2-10 mV accompanied by increase of AP frequency, prolongation of their duration and decrease of summmerized ionic currents (dV/dt). According to degree of depolarization, the drugs were placed in the following range in decreasing activity: compound 3 > compound 2 > compound 1. In identified pedal ganglion neurons (PPed1), compound 3 in contrast to other compounds induced hyperpolarization by 2-10 mV and blocked impulse activity. The amplitude of sodium and calcium channels was decreased by 7-15 %, in the same degree after application of all compounds exposed in concentration of 5 mM. Efflux potassium ionic currents were increased in dose-dependent manner and irreversibly about by 3-7 % assessed on amplitude indexes without changes in kinetic parameters after application of LCD. Therefore, the decrease of ionic current amplitudes was due to both depolarization of neurons and direct action of LCD on ionic channels. Thus, LCD possess membranotropic activity and can modulate functional state of neurons. In the study of chloride channels in cells culture of rat glioma C6 in vitro by patch-clamp method, GABA, glycine, β-alanine and their LCD 10 µM/l activated chloride channels, shifting equiliblium membrane potential of glioma cells from -90… -70 mV to -55... -60 mV. All compounds (transmitters and LCD) were placed in the following range: glycine > GABA > β-alanine and compound 1 > compound 3 > compound 2 according to descending activity. Therefore, the most active compounds activating Cl--channels were glycine and compound 1 (LCD). Glycine was shown to be coagonist GABA receptors and its litium salt possessed significant membranotropic activity.