Αρχειοθήκη ιστολογίου

Δευτέρα 9 Νοεμβρίου 2020

Impairments to Oligodendrocyte Clustering in the Supra- and Infragranular Layers of Field 10 of the Prefrontal Cortex in Schizophrenia

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Objectives. Intravital studies have shown that alterations to myelination in the gray matter of the cortex in schizophrenia are the most marked in the prefrontal cortex. The authors have previously observed a decrease in the number density of oligodendrocytes (ND OL) in layers 3 and 5 of field 10 of the prefrontal cortex in schizophrenia. Proliferation of oligodendrocyte precursors in the brains of adult animals and humans is known to lead to the formation of oligodendrocyte clusters (OLC) and this process is linked with function-dependent axon myelination. The aim of the present work was to determine ND OLC and the ratio of ND OLC to ND OL in the functionally diverse supra- and infragranular layers of field 10 in health and schizophrenia. Materials and methods. ND OLC was determined in layers 3a, 3b, and 3c (supragranular) and 5a (infragranular) of field 10 using an optical dissector on Nissl-stained sections in 17 cases of schizophrenia and 20 people without mental disorders. Results and conclusions. Decreases in ND OLC were seen in both the supra- (by 32%, p < 0.02, Duncan test) and the infragranular (by 50%, p < 0.001) sublayers of field 10 in schizophrenia as compared with the control group. A decrease in the ND OLC/ND OL ratio was significant only for sublayers 2a (p = 0.015) and 5a (p < 0.001). In the control group, ND OLC showed a significant correlation with ND OL in sublayers 3b, 3c, and 5a (R ≥ 0.59, p ≤ 0.006), while in the schizophrenia group only layer 5a showed a persisting positive correlation (R = 0.8, p = 0.00001) between measures. A deficit of OLC in field 10 in schizophrenia may be due to impaired proliferation and/or differentiat ion of OL precursors. The nature of the interaction between ND OLC and ND OL presumptively depends on the characteristics of the connections between the corresponding cortical sublayers and their changes in schizophrenia.

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Use of a Brain–Computer Interface + Exoskeleton Technology in Complex Multimodal Stimulation in the Rehabilitation of Stroke Patients

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Introduction. Studies of the potentials of brain–computer neural interface technology with an arm exoskeleton (BCNI) in training to motor imagery in the recovery of higher mental functions in patients constitute an interesting task. The effectiveness of multimodal stimulation including diverse information channels needs to be assessed, as this approach should promote stimulation of neuroplasticity and improvement to interhemisphere interactions. Objectives. To study the influences of multimodal stimulation using BCNI technologies on the restoration of cognitive functions in stroke patients. Materials and methods. A total of 44 stroke patients were studied and treated at periods of two months to two years after onset. Patients were divid ed into two groups with comparable main parameters: a study group (22 patients) and a reference group (22 patients). Patients of the study group underwent a program of complex multimodal stimulation including procedures using BCNI technologies, cognitive training, use of a stabilometric platform with biological feedback for the support reaction, and vibrotherapy. Patients of the reference group received only BCNI. Results. After treatment, statistically significant improvements in therapeutic results were obtained in the form of improvements in memory, attention, and visuospatial skills in patients of the study group as compared with those of the reference group. Conclusions. Questions of cognitive training using BCNI technologies are currently a relatively new direction in neurorehabilitation; the promising results obtained here provide evidence of the potential of this direction.

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Noopept and Piracetam on Depression

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The actions of the nootropes noopept and piracetam on depression of the acetylcholine-induced current in a cellular analog of habituation were studied. Mathematical modeling of experimental curves and their analysis using previously obtained results on the effects of inhibitors of different protein kinases and protein phosphatases on acquisition of depression of the acetylcholine-induced current in a cellular analog of habituation clarified the intracellular processes and targets on which these agents act.

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Parvalbumin-Containing Enteric Metasympathetic Neurons in Postnatal Ontogeny

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The calcium-binding protein parvalbumin is selectively expressed in various subpopulations of neurons in the central and peripheral nervous system. The localization and percentage composition of parvalbumin-immunoreactive neurons were determined in the metasympathetic enteric ganglia of the small and large intestine in rats of different ages (1, 10, 20, 30, and 60 days and two years). Parvalbumin-immunoreactive neurons were present in the intermuscular plexus during ontogeny, from birth to old age, and the percentage of these cells in the intermuscular plexus in the small intestine increased from day 10 to day 20 of life and in that of the large intestine in the first 10 days of life. Parvalbumin was absent from the submucous plexus of the small and large intestine in neonatal rats, but w as present from day 10. The percentage of parvalbumin-immunoreactive neurons in the submucous plexus increased between day 10 and day 20 of life. On aging, the proportions of parvalbumin-immunoreactive neurons in the intermuscular and submucous plexuses did not change significantly. Thus, the proportion of parvalbumin-immunopositive neurons in the intramural intestinal ganglia increased in early postnatal ontogeny. This increase is probably associated with the buffer role of parvalbumin in relation to Ca2+ ions.

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Interaction of Interoceptive Perception and Emotional Intelligence: A Functional Neuroimaging Study

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Impairments to nociception are currently regarded as the pathogenetic mechanism of psychosomatic disorders and as a potential therapeutic target. An aim of the present work was to investigate the functional cerebral grounds linking the perception of internal sensations and emotional intelligence. The interoceptive paradigm for detection of the heartbeat was modified, adapted to Russian, and used in conditions of functional MRI in middle-aged and elderly people without neurological or mental illness. All subjects carried out the Mayer–Salovey–Caruso emotional intelligence test. The level of emotional intelligence and the accuracy of heart rhythm detection were linked with activation of the right anterior insular cortex. This mediator role of the right anterior insular cortex in the int eraction between interoception and emotional processing indicates that it can be regarded as a neural correlate of this interaction in developing approaches to the prophylaxis and treatment of psychosomatic disorders.

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Genetic Features of Cerebral Stroke

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Recent years have seen an increase in interest in the identification of additional genetic factors for cerebral stroke. A large number of studies have been run with the aim of verifying genetic influences on the risk of developing both ischemic and hemorrhagic stroke. This article discusses the main genes for susceptibility and genetic polymorphisms associated with the development of this disease. An important role in the occurrence of stroke is played by genetic factors controlling the processes of inflammation, blood clotting, lipid metabolism, nitric oxide formation, the functioning of the renin–angiotensin–aldosterone system, and homeostasis. Complex analysis of a number of genes allows patients with the greatest predisposition to developing the disease to be identified with the a ims of providing state-of-the-art prophylaxis and reducing the burden of stroke.

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Efficacy of High-Frequency Rhythmic Transcranial Magnetic Stimulation in Endogenous Depressive Disorders at Juvenile Age

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Objectives. To seek neurophysiological predictors of the effi cacy of rhythmic transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex in patients with depressive disorders of different nosological categories. Materials and methods. A total of 34 juvenile patients (all male) with protracted treatment-refractory depressive states were studied. Investigation of patients used psychopathological and psychometric methods (Hamilton scale) and electroencephalography. The search for predictors of therapeutic efficacy was carried out using a wide range of neurophysiological indicators and different protocols for high-frequency rTMS (10 and 20 Hz). Results and conclusions. The most significant changes were identified on rTMS at 20 Hz. Favorable treatment effects on the EEG were found to correlate with higher spectral power in the α and β1 subranges.

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Models of Autism and Methods for Assessing Autistic-Like Behavior in Animals

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Autistic spectrum disorders (ASD), including autism, constitute a wide range of states and are associated with deficit to social communications, limited interests, and stereotypical behavior. The development of translational medicine and personalized approaches to the treatment of ASD combine the efforts of clinicians and basic scientists and push the direction of studies towards the molecular and genetic mechanisms of developmental disorders and the search for new marker molecules for targeted correction of these states, which are impossible without use of models of ASD in animals, especially rodents. This review describes the key genetic and pharmacological models of ASD in rodents which are actively utilized in experimental studies, along with the most important behavioral tests for as sessing deficits in social behavior, stereotypy, and autism-like states in experimental animals.

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Contributions of Different Spatial Modulations of Brightness Gradients to the Control of Visual Attention

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The targets of visual selective attention are the most informative parts of images. All new data in recent years have pointed to the importance of second-order features – spatial inhomogeneities in brightness gradients – in solving a variety of visual tasks. We addressed the problem of determining how priorities of second-order features are distributed from the point of view of attracting attention. All information from initial images of objects other than modulations of specific modalities was removed. As a result, each object was represented in three versions: images consisting of modulations of contrast, orientation, and spatial frequency. In experiment 1, images formed from modulations of different dimensionalities but with the same spatial frequency competed for attention. In exp eriment 2, modulations of the same dimensionality but different frequencies were used. The direction of the subject's attention was evaluated by recording eye movements. The first saccade after stimulus onset was assessed. The observations showed that in the object orientation discrimination task using pairs of sequential stimuli, images formed from modulations of contrast and orientation of lower spatial frequency had a significant advantage in competing for attention. This result is explained by the notion that in competing for attention, areas of images with greater amplitude of brightness gradient modulation had the advantage in competing for attention.

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Power Exercises as a Risk Factor for Parkinson’s Disease

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Objectives. To study links between physical status, the severity of motor impairments, and histories of power exercises of former sportsmen with Parkinson's disease (PD). Materials and methods. A total of 20 men with PD, 10 of whom had histories of involvement in power sports for more than 5 years in their youths and 10 of whom had no such histories, took part in the study. Detailed histories were taken from all patients, particularly in relation to concomitant arterial hypertension; body mass index was determined, and hand dynamometry and the orthostatic test were performed. Motor function was assessed using the PD scale (MDS UPDRS part III). Results and conclusions. Patients with sporting histories, in contrast to non-sporting patient s, were younger (57.44 ± 8.14 years vs. 66.78 ± 4.29 years, p < 0.05), and had longer durations of disease (6.56 ± 5.36 years vs. 3.60 ± 3.5 years, p < 0.05). The orthostatic reaction in former sportsmen was accompanied by an increase in diastolic arterial blood pressure (SBP), while men who had not been involved in sports had a decrease in SBP. Hypokinetic syndrome was significantly more marked in former sportsmen, where slow movements (bradykinesia) rated 3 points on the MDS UPDRS in six cases and 4 points in four. The results obtained here demonstrate that power sports prior to disease onset had a significant influence of the development and signs of PD.

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Thermogenetics as a New Direction in Controlling the Activity of Neural Networks

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Thermogenetics appeared recently as an evolutionary advance in methods of optical stimulation of nerve cells and uses focused light to activate light-sensitive cation channels in the neuron membrane. Light activation and opening of light-sensitive channels, which can be expressed genetically in any type of neuron, induces neuron membrane depolarization and a resultant action potential. In contrast to classical methods of optogenetics, which use the visible spectrum, thermogenetics uses channels sensitive to warming. This provides the opportunity for additional activation of these channels not only using IR light, but also other methods of warming nervous tissue, such as ultrasound or microwave radiation. The penetrability of living tissue to stimulation with IR radiation is an order of ma gnitude greater than that for visible spectrum radiation, which allows thermogenetics methods to be used in vivo without invasive surgical methods to "clear the way" for optogenetic stimulation. On the other hand, the thermal nature of the stimulation imposes additional limits on use of the method, as heating must be sufficiently gentle so as not to induce heat shock at the cellular level, and the threshold of activation must be sufficiently high for channel opening not to occur spontaneously at normal physiological temperatures.

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Gly-Pro and Adaptive Reactions in Multicomponent Stress

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We report here studies on the effects of the peptide glycylproline (Gly-Pro) on measures of reactivity and adaptive potential on stimulation of the parasympathetic nervous system with carbachol in conditions of sequential exposure to the combined actions of three stress factors: immobilization, surgery, and an injection procedure. Sequential combination of surgery (application of a ligature to the pylorus of the stomach), immobilization, and the procedure of injecting physiological saline on the background of carbachol allowed four types of response in rats to be identified. These variants were characterized by different combinations of levels of corticosterone and different leukocyte subpopulations. All response variants were accompanied by development of stress, as indicated by the adap tation intensity index. The most profound stress reactions were seen in animals after immobilization and surgery and the combination of injection of physiological saline and carbachol. By modulating the parasympathetic compartment of the autonomic nervous system and, probably, a direct influence on the adrenals, Gly-Pro altered the corticosterone content and different leukocyte subpopulations and the adaptation intensity index in multicomponent stress. When peptide was given simultaneously with carbachol, it appeared to act via the resistance (counteraction) pathway of adaption, while when given in advance, before carbachol, it operated via the tolerance (stamina, endurance) pathway.

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