scholarly journals Rabies anterograde monosynaptic tracing reveals organization of spinal sensory circuits

2021 ◽  
Author(s):  
Sofia Pimpinella ◽  
Niccolò Zampieri

AbstractSomatosensory neurons detect vital information about the environment and internal status of the body, such as temperature, touch, itch and proprioception. The circuit mechanisms controlling the coding of somatosensory information and the generation of appropriate behavioral responses are not clear yet. In order to address this issue, it is important to define the precise connectivity patterns between primary sensory afferents dedicated to the detection of different stimuli and recipient neurons in the central nervous system. In this study we used a rabies tracing approach for mapping spinal circuits receiving sensory input from distinct, genetically defined, modalities. We analyzed the anatomical organization of spinal circuits involved in coding of thermal and mechanical stimuli and showed that somatosensory information from distinct modalities is relayed to partially overlapping ensembles of interneurons displaying stereotyped laminar organization, thus highlighting the importance of positional features and population coding for the processing and integration of somatosensory information.

1938 ◽  
Vol 15 (3) ◽  
pp. 339-357
Author(s):  
H. O. J. COLLIER

1. In response to stimuli at the head, a peristaltic wave travelling in any part of the earthworm's body may be arrested. This occurs after an interval of about 0.5 sec., if the nearest part of the wave is 5 cm. from the point of stimulus. This response is of regular occurrence, and it depends on the continuity of the nerve cord between the point of stimulus and the region of the wave. It is therefore named the reflex arrest of peristalsis. 2. The arrest of peristalsis is brought about by the complete cessation of movement of both the elongation phase and the shortening phase of the wave. The shape of the wave is not lost; though it appears that there may be some relaxation of the circular muscles in the region of elongation. 3. The receptors of the reflex lie on the cephalic half of the body. Stimuli applied on the most cephalic one-third of the body may arrest a peristaltic wave cephalic to their point of application. 4. The response may appear in answer to mechanical or to chemical stimuli. It may also appear in response to the absence of contact with the substratum in the head region. In this last case the reflex depends upon the presence of the supraoesophageal ganglion. The response to mechanical stimuli, however, depends neither on the presence of the cephalic one-third of the body, nor on the presence of the tail segments. 5. A similar reflex arrest of anti-peristalsis occurs in response to mechanical or chemical stimuli on the caudal half of the body. The time interval between stimulus and response at 5 cm. from the point of stimulus is about 0.4 sec. The anti-peristaltic wave was not observed to be arrested while travelling in the most cephalic one-third of the body. 6. The arrest of the anti-peristaltic wave is due, too, to a cessation of movement of both phases of the wave, without a loss of its general shape. 7. The receptors for the reflex lie in the caudal half of the body, and the nerve paths from them run in both directions. The reflex does not depend on the presence of either the head or the tail segments. It can be obtained in a worm with the most caudal one-third of the body removed, or in a worm with the most cephalic one-third cut off. 8. The arrest of an anti-peristaltic wave by the development of a peristaltic wave can be observed in the spontaneous reversal of the direction of crawling. This act of behaviour, which is named the spontaneous immobilization of anti-peristalsis, does not depend on the presence of either the most cephalic one-third or the most caudal one-third of the body. Though this act of behaviour need not be considered as a reflex, its performance depends on the continuity of the nerve cord between the new peristaltic wave and the anti-peristaltic wave that is immobilized. 9. The above three acts of behaviour are distinct from each other in their paths in the cord, and the two reflexes are distinct in their receptors. All three play an important part in one or more larger patterns of behaviour. All are conducted in paths separate from those conducting the rapid shortening reflexes. 10. There is little evidence to throw light on the mode of action of these three immobilizations. They may be compared to the "freezing" of movement into posture found in insects and vertebrates. It is to be expected that their mechanism will prove to lie within the central nervous system.


Author(s):  
F. L. Azizova ◽  
U. A. Boltaboev

The features of production factors established at the main workplaces of shoe production are considered. The materials on the results of the study of the functional state of the central nervous system of women workers of shoe production in the dynamics of the working day are presented. The level of functional state of the central nervous system was determined by the speed of visual and auditory-motor reactions, installed using the universal device chronoreflexometer. It was revealed that in the body of workers of shoe production there is an early development of inhibitory processes in the central nervous system, which is expressed in an increase in the number of errors when performing tasks on proofreading tables. It was found that the most pronounced shift s in auditory-motor responses were observed in professional groups, where higher levels of noise were registered in the workplace. The correlation analysis showed a close direct relationship between the growth of mistakes made in the market and the decrease in production. An increase in the time spent on the task indicates the occurrence and growth of production fatigue.Funding. The study had no funding.Conflict of interests. The authors declare no conflict of interests.


Author(s):  
RR Galimova ◽  
ET Valeeva ◽  
GV Timasheva ◽  
AB Bakirov

Introduction: Production of ethylbenzene and styrene (EBS) is one of the most important stages in organic synthesis. The products have general toxic, hepatotoxic, irritating and narcotic effects on the human body. Severe exposures to EВS can induce pronounced disorders of the central nervous system such as styrene sickness and encephalopathy and of peripheral blood such as leukopenia and lymphocytosis. Materials and methods: We studied homeostasis indices in 376 workers of the main professional groups engaged in the production of EBS including equipment operators, repairmen, and instrumentation and automation fitters. Results: We established an increase in lipid peroxidation by the level of malondialdehyde amid an increase in catalase activity and a decrease in blood retinol and α-tocopherol levels. We also noted an increased activity of indicator enzymes including ALT, AST, GGT, and alkaline phosphatase. Significant changes in lipid metabolism in the form of cholesterolemia, triglyceridemia, a higher atherogenic index, and lower cholesterol of non-atherogenic blood serum lipids demonstrating atherogenic changes in the body were revealed. Conclusions: The earliest prenosological disorders in the body of the examined workers included an impaired hepatic protein synthesis, the development of cytolysis processes and a change in the integrity and functional activity of the liver cell in individuals, an imbalance in the oxidant-antioxidant system, one of the reasons of which was the adverse occupational exposure to hazardous chemicals. An increase in catalase activity is a protective compensatory reaction during the activation of free radical oxidation processes.


Author(s):  
Prithiv K R Kumar

Stem cells have the capacity to differentiate into any type of cell or organ. Stems cell originate from any part of the body, including the brain. Brain cells or rather neural stem cells have the capacitive advantage of differentiating into the central nervous system leading to the formation of neurons and glial cells. Neural stem cells should have a source by editing DNA, or by mixings chemical enzymes of iPSCs. By this method, a limitless number of neuron stem cells can be obtained. Increase in supply of NSCs help in repairing glial cells which in-turn heal the central nervous system. Generally, brain injuries cause motor and sensory deficits leading to stroke. With all trials from novel therapeutic methods to enhanced rehabilitation time, the economy and quality of life is suppressed. Only PSCs have proven effective for grafting cells into NSCs. Neurons derived from stem cells is the only challenge that limits in-vitro usage in the near future.


2020 ◽  
Vol 20 (13) ◽  
pp. 1142-1153 ◽  
Author(s):  
Sreyashi Chandra ◽  
Md. Tanjim Alam ◽  
Jhilik Dey ◽  
Baby C. Pulikkaparambil Sasidharan ◽  
Upasana Ray ◽  
...  

Background: The central nervous system (CNS) known to regulate the physiological conditions of human body, also itself gets dynamically regulated by both the physiological as well as pathological conditions of the body. These conditions get changed quite often, and often involve changes introduced into the gut microbiota which, as studies are revealing, directly modulate the CNS via a crosstalk. This cross-talk between the gut microbiota and CNS, i.e., the gut-brain axis (GBA), plays a major role in the pathogenesis of many neurodegenerative disorders such as Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS) and Huntington’s disease (HD). Objective: We aim to discuss how gut microbiota, through GBA, regulate neurodegenerative disorders such as PD, AD, ALS, MS and HD. Methods: In this review, we have discussed the present understanding of the role played by the gut microbiota in neurodegenerative disorders and emphasized the probable therapeutic approaches being explored to treat them. Results: In the first part, we introduce the GBA and its relevance, followed by the changes occurring in the GBA during neurodegenerative disorders and then further discuss its role in the pathogenesis of these diseases. Finally, we discuss its applications in possible therapeutics of these diseases and the current research improvements being made to better investigate this interaction. Conclusion: We concluded that alterations in the intestinal microbiota modulate various activities that could potentially lead to CNS disorders through interactions via the GBA.


Author(s):  
Richard A. Dienstbier ◽  
Lisa M. Pytlik Zillig

This chapter presents an overview of the concept of toughness, which at the abstract level is about the harmony of physiological systems, and more concretely is about how the body influences the mind. Toughness theory begins with the recognition that there is a “training effect” for neuroendocrine systems. Following a review of the characteristics of interventions and training programs that can promote toughness, the authors present a model in which the effects of toughness are mediated by neuroendocrine systems such as the pituitary-adrenal-cortical system and the central nervous system. The elements of toughness (e.g., having a greater capacity for arousal and energy when needed) are proposed to promote positive outcomes by facilitating the use of adaptive coping strategies and improving emotional stability. Toughness therefore appears to be a promising concept within positive psychology in that it helps to explain how the dynamic interactions between psychological and somatic processes can promote positive outcomes.


2021 ◽  
Vol 22 (13) ◽  
pp. 6858
Author(s):  
Fanny Gaudel ◽  
Gaëlle Guiraudie-Capraz ◽  
François Féron

Animals strongly rely on chemical senses to uncover the outside world and adjust their behaviour. Chemical signals are perceived by facial sensitive chemosensors that can be clustered into three families, namely the gustatory (TASR), olfactory (OR, TAAR) and pheromonal (VNR, FPR) receptors. Over recent decades, chemoreceptors were identified in non-facial parts of the body, including the brain. In order to map chemoreceptors within the encephalon, we performed a study based on four brain atlases. The transcript expression of selected members of the three chemoreceptor families and their canonical partners was analysed in major areas of healthy and demented human brains. Genes encoding all studied chemoreceptors are transcribed in the central nervous system, particularly in the limbic system. RNA of their canonical transduction partners (G proteins, ion channels) are also observed in all studied brain areas, reinforcing the suggestion that cerebral chemoreceptors are functional. In addition, we noticed that: (i) bitterness-associated receptors display an enriched expression, (ii) the brain is equipped to sense trace amines and pheromonal cues and (iii) chemoreceptor RNA expression varies with age, but not dementia or brain trauma. Extensive studies are now required to further understand how the brain makes sense of endogenous chemicals.


Author(s):  
Jeffrey T. Bingham ◽  
Marco P. Schoen

Human muscle motion is initiated in the central nervous system where a nervous signal travels through the body and the motor neurons excite the muscles to move. These signals, termed myoelectric signals, can be measured on the surface of the skin as an electrical potential. By analyzing these signals it is possible to determine the muscle actions the signals elicit, and thus can be used in manipulating smart prostheses and teleoperation of machinery. Due to the randomness of myoelectric signals, identification of the signals is not complete, therefore the goal of this project is to complete a study of the characterization of one set of hand motions using current system identification methods. The gripping motion of the hand and the corresponding myoelectric signals are measured and the data captured with a personal computer. Using computer software the captured data are processed and finally subjected to several system identification routines. Using this technique it is possible to construct a mathematical model that correlates the myoelectric signals with the matching hand motion.


In the study of the phenomena of anaphylaxis there are certain points on which some measure of agreement seems to have been attained. In the case of anaphylaxis to soluble proteins, with which alone we are directly concerned in this paper, the majority of investigators probably accept the view that the condition is due to the formation of an antibody of the precipitin type. Concerning the method, however, by which the presence of this antibody causes the specific sensitiveness, the means by which its interaction with the antibody produces the anaphylactic shock, there is a wide divergence of conception. Two main currents of speculation can be discerned. One view, historically rather the earlier, and first put forward by Besredka (1) attributes the anaphylactic condition to the location of the antibody in the body cells. There is not complete unanimity among adherents of this view as to the nature of the antibody concerned, or as to the class of cells containing it which are primarily affected in the anaphylactic shock. Besredka (2) himself has apparently not accepted the identification of the anaphylactic antibody with a precipitin, but regards it as belonging to a special class (sensibilisine). He also regards the cells of the central nervous system as those primarily involved in the anaphylactic shock in the guinea-pig. Others, including one of us (3), have found no adequate reason for rejecting the strong evidence in favour of the precipitin nature of the anaphylactic antibody, produced by Doerr and Russ (4), Weil (5), and others, and have accepted and confirmed the description of the rapid anaphylactic death in the guinea-pig as due to a direct stimulation of the plain-muscle fibres surrounding the bronchioles, causing valve-like obstruction of the lumen, and leading to asphyxia, with the characteristic fixed distension of the lungs, as first described by Auer and Lewis (6), and almost simultaneously by Biedl and Kraus (7). But the fundamental conception of anaphylaxis as due to cellular location of an antibody, and of the reaction as due to the union of antigen and antibody taking place in the protoplasm, is common to a number of workers who thus differ on details.


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