Central neurophysiological processing of joint pain on the basis of studies performed in normal animals and in models of experimental arthritis

1991 ◽  
Vol 69 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Gisèle Guilbaud
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Joint Pain ◽  
Somatosensory System ◽  
Mechanical Stimuli ◽  
Neuronal Responses ◽  
Neuronal Populations ◽  
Electrophysiological Studies ◽  
The Central Nervous System ◽  
Different Levels

On the basis of anatomical and electrophysiological studies, this review summarizes first, the data dealing with the transmission of joint inputs in the central nervous system of normal animals at the spinal and supraspinal levels. It appears that in these conditions neuronal responses to mechanical noxious stimuli of the joints are relatively few and (or) weak. Second, in sharp contrast, the studies performed in polyarthritic rats have emphasized the profound changes in the activities (spontaneous firing and responsiveness) of the somatosensory neurones at various levels of the central nervous system (CNS), including the thalamus and primary somatosensory cortex; many were spontaneously active and a majority of them could be maximally activated by gentle mechanical stimuli applied to the inflamed joints. Although the change in the sensitivity of the peripheral mechanoreceptors has a major role in the modifications described in the CNS, additional observations have suggested a complex interaction between peripheral and central processes. On the basis of the recent data obtained in poly- and mono-arthritic animals, the following phenomena have been successively considered: the segmental and hetero-segmental "cross-talk" and their possible relationship with referred pain; the involvement of "new" neuronal populations as a possible basis of a selective system for joint pain; and the possible involvement of changes in the various control systems that normally modulate the nociceptive inputs at different levels of the CNS.Key words: joint pain, electrophysiology, somatosensory system, thalamus, rat.

Leech Mechanosensation

2017 ◽  
Author(s):  
Brian D. Burrell
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Neurons ◽  
Receptive Fields ◽  
Model Systems ◽  
Sensory Cells ◽  
Mechanical Stimuli ◽  
Nociceptive Neurons ◽  
Mechanosensory Neurons ◽  
The Central Nervous System

The medicinal leech (Hirudo verbana) is an annelid (segmented worm) and one of the classic model systems in neuroscience. It has been used in research for over 50 years and was one of the first animals in which intracellular recordings of mechanosensory neurons were carried out. Remarkably, the leech has three main classes of mechanosensory neurons that exhibit many of the same properties found in vertebrates. The most sensitive of these neurons are the touch cells, which are rapidly adapting neurons that detect low-intensity mechanical stimuli. Next are the pressure cells, which are slow-adapting sensory neurons that respond to higher intensity, sustained mechanostimulation. Finally, there are nociceptive neurons, which have the highest threshold and respond to potentially damaging mechanostimuli, such as a pinch. As observed in mammals, the leech has separate mechanosensitive and polymodal nociceptors, the latter responding to mechanical, thermal, and chemical stimuli. The cell bodies for all three types of mechanosensitive neurons are found in the central nervous system where they are arranged as bilateral pairs. Each neuron extends processes to the skin where they form discrete receptive fields. In the touch and pressure cells, these receptive fields are arranged along the dorsal-ventral axis. For the mechano-only and polymodal nociceptive neurons, the peripheral receptive fields overlap with the mechano-only nociceptor, which also innervates the gut. The leech also has a type of mechanosensitive cell located in the periphery that responds to vibrations in the water and is used, in part, to detect potential prey nearby. In the central nervous system, the touch, pressure, and nociceptive cells all form synaptic connections with a variety of motor neurons, interneurons, and even each other, using glutamate as the neurotransmitter. Synaptic transmission by these cells can be modulated by a variety of activity-dependent processes as well as the influence of neuromodulatory transmitters, such as serotonin. The output of these sensory neurons can also be modulated by conduction block, a process in which action potentials fail to propagate to all the synaptic release sites, decreasing synaptic output. Activity in these sensory neurons leads to the initiation of a number of different motor behaviors involved in locomotion, such as swimming and crawling, as well as behaviors designed to recoil from aversive/noxious stimuli, such as local bending and shortening. In the case of local bending, the leech is able to bend in the appropriate direction away from the offending stimuli. It does so through a combination of which mechanosensory cell receptive fields have been activated and the relative activation of multiple sensory cells decoded by a layer of downstream interneurons.

Electrophysiology of the central and peripheral nervous systems

2020 ◽  
pp. 5785-5802
Author(s):  
Christian Krarup
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Nerve Conduction Studies ◽  
Brain Diseases ◽  
The Core ◽  
Electrophysiological Studies ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
The Brain

This chapter looks at electrophysiological studies of the central nervous system and peripheral nervous system—the core investigations in clinical neurophysiology. These include electroencephalography, which is of value to diagnose epilepsy caused by focal or diffuse brain diseases, electromyography and nerve conduction studies, which are of value to diagnose diseases in nerves and muscles, and evoked potentials, which are of value to diagnose diseases of white matter in the brain and spinal cord.

scholarly journals Neuronal sensitivity to hyperoxia, hypercapnia, and inert gases at hyperbaric pressures

2003 ◽  
Vol 95 (3) ◽  
pp. 883-909 ◽  
Author(s):  
Jay B. Dean ◽  
Daniel K. Mulkey ◽  
Alfredo J. Garcia ◽  
Robert W. Putnam ◽  
Richard A. Henderson
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ambient Pressure ◽  
Inert Gases ◽  
Neuronal Function ◽  
Cellular Mechanisms ◽  
Electrophysiological Studies ◽  
The Central Nervous System ◽  
Electrophysiological Methods

As ambient pressure increases, hydrostatic compression of the central nervous system, combined with increasing levels of inspired Po2, Pco2, and N2partial pressure, has deleterious effects on neuronal function, resulting in O2toxicity, CO2toxicity, N2narcosis, and high-pressure nervous syndrome. The cellular mechanisms responsible for each disorder have been difficult to study by using classic in vitro electrophysiological methods, due to the physical barrier imposed by the sealed pressure chamber and mechanical disturbances during tissue compression. Improved chamber designs and methods have made such experiments feasible in mammalian neurons, especially at ambient pressures <5 atmospheres absolute (ATA). Here we summarize these methods, the physiologically relevant test pressures, potential research applications, and results of previous research, focusing on the significance of electrophysiological studies at <5 ATA. Intracellular recordings and tissue Po2measurements in slices of rat brain demonstrate how to differentiate the neuronal effects of increased gas pressures from pressure per se. Examples also highlight the use of hyperoxia (≤3 ATA O2) as a model for studying the cellular mechanisms of oxidative stress in the mammalian central nervous system.

Neuropathic Pain Syndromes

2021 ◽  
pp. 901-905
Author(s):  
James C. Watson
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neuropathic Pain ◽  
Peripheral Nervous System ◽  
Sensitivity And Specificity ◽  
International Association ◽  
Somatosensory System ◽  
Pain Syndromes ◽  
The Central Nervous System ◽  
Pain Descriptors

The International Association for the Study of Pain defines neuropathic pain as pain that is initiated or caused by a lesion or disease affecting the somatosensory system in either the peripheral nervous system or the central nervous system. Several well-recognized descriptors for neuropathic pain suggest a neuropathic rather than nociceptive pathophysiology (hot, burning, painful cold, freezing, prickling or tingling, pins and needles, electrical, shooting, stabbing, lancinating, and itching). However, whether the pain descriptors are used alone or incorporated into questionnaires to identify neuropathic pain, their sensitivity and specificity are limited (generally 70%-85%); therefore, verbal pain descriptors are insufficient for making the diagnosis of neuropathic pain.

scholarly journals Biomedical applications of voice and speech processing

Loquens ◽  
2017 ◽  
Vol 4 (1) ◽  
pp. 035
Author(s):  
Pedro Gómez Vilda
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neurodegenerative Diseases ◽  
Speech Processing ◽  
Clear Cut ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
Anatomic Localization ◽  
Different Levels ◽  
Lateral Sclerosis

Neurological deterioration presents different variants depending on their classification criterion, which may be their anatomic localization or their disease clinical features, although there is not a clear cut between both. Anatomically this ample group of disorders may affect the central nervous system (brain and spinal cord), or the peripheral nervous system. Clinically, the neurodegenerative disorders are classified as affecting cognitive functions or neuromotor capabilities. In the group of neurodegenerative diseases of the central nervous system, Alzheimer’s disease (AD) or Fronto-Temporal Dementia (FTD) are to be found, whereas in the second group certain pathologies as Parkinson’s Disease (PD), Amyotrophic Lateral Sclerosis (ALS), Huntington’s Disease (HD) or myasthenia gravis (MG) are among the most frequent ones, although “the number of neurodegenerative diseases is currently estimated to be a few hundred” (Przedborski et al., 2003). All these pathologies produce correlates in speech at different levels: in fluency, in prosody, in articulation or in phonation. Speech technologies offer computer solutions to evaluate objectively detected anomalies in each level, adding statistical robustness, which makes them suitable for their clinical and rehabilitative application. The present issue is devoted to briefly review the characteristics of the diseases mentioned before, defining the foundations of the correlate features present in each one. Some computer solutions available in detecting and monitoring illness progress are reviewed in the contributions of different research groups working in this field.

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