scholarly journals Development and aging of human spinal cord circuitries

2017 ◽  
Vol 118 (2) ◽  
pp. 1133-1140 ◽  
Author(s):  
Svend Sparre Geertsen ◽  
Maria Willerslev-Olsen ◽  
Jakob Lorentzen ◽  
Jens Bo Nielsen
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Early Development ◽  
The Body ◽  
Physiological Changes ◽  
Human Spinal Cord ◽  
Spinal Motor ◽  
The World ◽  
New Challenges ◽  
Development And Aging

The neural motor circuitries in the spinal cord receive information from our senses and the rest of the nervous system and translate it into purposeful movements, which allow us to interact with the rest of the world. In this review, we discuss how these circuitries are established during early development and the extent to which they are shaped according to the demands of the body that they control and the environment with which the body has to interact. We also discuss how aging processes and physiological changes in our body are reflected in adaptations of activity in the spinal cord motor circuitries. The complex, multifaceted connectivity of the spinal cord motor circuitries allows them to generate vastly different movements and to adapt their activity to meet new challenges imposed by bodily changes or a changing environment. There are thus plenty of possibilities for adaptive changes in the spinal motor circuitries both early and late in life.

Plasticity in the Regenerating Nervous System of the Lamprey, a “Simple” Vertebrate

2018 ◽  
Author(s):  
William Rodemer ◽  
Jianli Hu ◽  
Michael E. Selzer
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Axon Regeneration ◽  
Test Bed ◽  
Human Spinal Cord ◽  
Human Genes ◽  
Cord Injury ◽  
The Face ◽  
Descending Input ◽  
Severed Axons

Human spinal cord injury (SCI) results in long-lasting disabilities due to the failure of damaged neurons to regenerate. The barriers to axon regeneration in mammalian central nervous system (CNS) are so great, and the anatomy so complex that incremental changes in regeneration brought about by pharmacological or molecular manipulations can be difficult to demonstrate. By contrast, lampreys recover functionally after a complete spinal cord transection (TX), based on regeneration of severed axons, even though lampreys share the basic organization of the mammalian CNS, including many of the same molecular barriers to regeneration. And because the regeneration is incomplete, it can be studied by manipulations designed to either inhibit or enhance it. In the face of reduced descending input, recovery of swimming and other locomotor functions must be accompanied by compensatory remodeling throughout the CNS, as would be required for functional recovery in mammals. For such studies, lampreys have significant advantages. They have several large, identified reticulospinal (RS) neurons, whose regenerative abilities have been individually quantified. Other large neurons and axons are visible in the spinal cord and can be impaled with microelectrodes under direct microscopic vision. The central pattern generator for locomotion is exceptionally well-defined, and is subject to significant neuromodulation. Finally, the lamprey genome has been sequenced, so that molecular homologs of human genes can be identified and cloned. Because of these advantages, the lamprey spinal cord has been a fertile source of information about the biology of axon regeneration in the vertebrate CNS, and has the potential to serve as a test bed for the investigation of novel therapeutic approaches to SCI and other CNS injuries.

scholarly journals Geoffrey Raisman. 28 June 1939—27 January 2017

2018 ◽  
Vol 65 ◽  
pp. 341-355
Author(s):  
James Fawcett
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Glial Cells ◽  
Spinal Cord Injuries ◽  
Axon Regeneration ◽  
Scar Tissue ◽  
Human Spinal Cord ◽  
New Energy ◽  
Spinal Cord Repair ◽  
The Brain

Geoffrey Raisman was a neuroscientist whose particular love was the microanatomy and ultrastructure of the nervous system. From his anatomical studies came discoveries in synaptic plasticity, neuroendocrinology, axon regeneration, spinal cord repair and glaucoma. His studies of the anatomy of synapses after denervation led to his concept of plasticity, where synapses compete for targets and can replace those that are lost. This discovery persuaded him, against the dominant view of the time, that some repair of the damaged nervous system should be possible. His studies of the events following damage to the nervous system led to the pathway hypothesis; axon regeneration is blocked by scar tissue formed of glial cells around injuries. Finding that the newly born olfactory neurons that are created throughout life grow axons into the brain with the assistance of specialized olfactory glia, he realized that these glial cells might also assist regenerating axons to bridge the scar tissue blocking axon regeneration. Preliminary trials of this treatment in human spinal cord injuries have shown some clinical promise. He recently developed a new energy theory of glaucoma.

scholarly journals Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal)

2016 ◽  
Vol 115 (5) ◽  
pp. 2421-2433 ◽  
Author(s):  
Anne-Christine Schmid ◽  
Jui-Hong Chien ◽  
Joel D. Greenspan ◽  
Ira Garonzik ◽  
Nirit Weiss ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Nervous System ◽  
Single Neuron ◽  
The Body ◽  
Neuronal Responses ◽  
Tactile Stimuli ◽  
Sensory Nucleus ◽  
Tactile Sensations ◽  
Sensory Abnormality

The normal organization and plasticity of the cutaneous core of the thalamic principal somatosensory nucleus (ventral caudal, Vc) have been studied by single-neuron recordings and microstimulation in patients undergoing awake stereotactic operations for essential tremor (ET) without apparent somatic sensory abnormality and in patients with dystonia or chronic pain secondary to major nervous system injury. In patients with ET, most Vc neurons responded to one of the four stimuli, each of which optimally activates one mechanoreceptor type. Sensations evoked by microstimulation were similar to those evoked by the optimal stimulus only among rapidly adapting neurons. In patients with ET, Vc was highly segmented somatotopically, and vibration, movement, pressure, and sharp sensations were usually evoked by microstimulation at separate sites in Vc. In patients with conditions including spinal cord transection, amputation, or dystonia, RFs were mismatched with projected fields more commonly than in patients with ET. The representation of the border of the anesthetic area (e.g., stump) or of the dystonic limb was much larger than that of the same part of the body in patients with ET. This review describes the organization and reorganization of human Vc neuronal activity in nervous system injury and dystonia and then proposes basic mechanisms.

scholarly journals Regeneration of spinal motor axons: Negative regulation by Celsr2 implicating Cdc42/Rac1 and JNK/c-Jun signaling

2021 ◽  
Author(s):  
Quan Wen ◽  
Huandi Weng ◽  
Tao Liu ◽  
Lingtai Yu ◽  
Tainyun Zhao ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Axon Regeneration ◽  
Neuromuscular Junctions ◽  
Motor Axon ◽  
Neural Repair ◽  
Human Spinal Cord ◽  
Spinal Motor ◽  
Motor Neuron Survival ◽  
Injury Model

AbstractDuring development, cadherins Celsr2 and Celsr3 control axon navigation. Unlike Celsr3, Celsr2 remains expressed in the adult, suggesting unexplored roles in maintenance and repair. Here we show that Celsr2 knockdown promotes motor axon regeneration in mouse and human spinal cord explants and cultured motor neurons. Celsr2 downregulation is accompanied by increased levels of GTP-bound Rac1 and Cdc42, and of JNK and c-Jun proteins. Using a branchial plexus injury model, we show that forelimb functional recovery is improved in Celsr2 mutant versus control mice. Compared to controls, in mutant mice, reinnervated biceps muscles are less atrophic, contain more newly formed neuromuscular junctions, and generate larger electromyographic potentials, while motor neuron survival and axon regeneration are improved. GTP-bound Rac1 and Cdc42, JNK and c-Jun are upregulated in injured mutant versus control spinal cord. In conclusion, Celsr2 negatively regulates motor axon regeneration via Cdc42/Rac1/JNK/c-Jun signaling and is a target for neural repair.

Introduction to the Nervous System

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
The Body ◽  
Conscious Awareness ◽  
Sensory Stimuli ◽  
System P ◽  
Brainstem Stroke ◽  
Primary Deficit ◽  
The Central Nervous System ◽  
The Brain

The primary regions and principal functions of the central nervous system are introduced through the story of Jean-Dominique Bauby who became locked in after suffering a brainstem stroke. Bauby blinked out his story of locked-in syndrome one letter at a time. The primary deficit of locked-in syndrome is in voluntary movement because pathways from the brain to motoneurons in the brainstem and spinal cord are interrupted. Perception is also disturbed as pathways responsible for transforming sensory stimuli into conscious awareness are interrupted as they ascend through the brainstem into the forebrain. Homeostasis, through which the brain keeps the body alive, is also adversely affected in locked-in syndrome because it depends on the brain, spinal cord and autonomic nervous system. Abstract functions such as memory, language, and emotion depend fully on the forebrain and are intact in locked-in syndrome, as clearly evidenced by Bauby’s eloquent words.

Why and How Do We Hurt?

2002 ◽  
Author(s):  
Daniel J. Wallace ◽  
Janice Brock Wallace
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Clinical Situation ◽  
The Body ◽  
Sensory Pathways ◽  
System P ◽  
Chronic Pain Patients ◽  
The Central Nervous System ◽  
Pain Patients ◽  
The Brain

A fibromyalgia patient frequently complains of pain. The pain of fibromyalgia is different from that of a headache, stomach cramp, toothache, or swollen joint. It has been described as a type of stiffness or aching, often associated with spasm. Unlike the other pains mentioned above, fibromyalgia pain responds poorly to aspirin, acetaminophen (Tylenol), or ibuprofen (Advil, Motrin). In fact, studies have suggested that even narcotics such as morphine are minimally beneficial in ameliorating fibromyalgia pain. Why is it that fibromyalgia patients can take codeine, Darvon, Vicodin, or even Demerol for musculoskeletal aches and have only a slight response? What produces “pain without purpose”? In this chapter, we’ll explore what makes fibromyalgia a pain amplification syndrome. Why does the patient hurt in places where there was often no injury and all laboratory tests are normal? What creates what doctors call allodynia, or a clinical situation that results in pain from a stimulus (such as light touch) that normally should not be painful? Fibromyalgia is a form of chronic, widespread allodynia, as well as sustained hyperalgesia, or greater sensitivity than would be expected to an adverse stimulus. The nervous system consists of several components. The brain and spinal cord comprise the central nervous system. Nerves leaving the spinal cord that tell us to move our arms or legs are part of the “motor” aspects of the peripheral nervous system. Additionally, all sorts of information about touch, taste, chemicals, and pressure are relayed through “sensory” pathways back to the spinal cord, where they are processed and sent up to the brain for a response. The autonomic nervous system consists of specialized peripheral nerves. Fibromyalgia is a disorder characterized by an inappropriate neuromuscular reaction that leads to chronic pain. Patients with fibromyalgia usually react normally to acute pain. Our current concepts of the way the body responds to chronic painful stimuli stem from the gate theory, first proposed by Ronald Melzack and Patrick Wall in 1965. Nerve “wires” go from the periphery to the dorsal horn of the spinal cord. These wires are modulated by feedback loops within the nervous system.

6. From thought to action

2021 ◽  
pp. 89-103
Author(s):  
Jamie A. Davies
Keyword(s):  
Skeletal Muscle ◽  
Nervous System ◽  
Musculoskeletal System ◽  
Muscle Cells ◽  
Mechanical Force ◽  
The Body ◽  
Chemical Energy ◽  
Whole Body ◽  
The World ◽  
Ultimate Result

This chapter addresses muscles. The ultimate result of sensation and thought is usually some kind of action, be it moving the whole body; manipulating an object with the hand; or moving diaphragm, mouth, tongue, and voice-box to speak. All of these depend on muscles which, in their various forms, provide a nearly universal means for the nervous system to control the body and the world. Muscle cells are highly adapted for turning chemical energy into mechanical force. The chapter then looks at skeletal muscle and the musculoskeletal system. Some muscles are arranged circumferentially around a cavity. Two examples of this are the heart and the gut.

Spinal Cord Injuries the Facts of Neuropathology: Opportunities and Limitations

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Byron A Kakulas
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Nervous System ◽  
Wallerian Degeneration ◽  
Spinal Cord Injuries ◽  
Neurological Status ◽  
Research Projects ◽  
Human Spinal Cord ◽  
The Third ◽  
Cord Injury

It is essential for research projects which are undertaken to find a “cure” for human spinal cord injury (SCI) to be consistent with the neuropathological facts of the disorder. In this respect there are three main points to be taken into account. Firstly, the researcher should be aware that simple transection of the spinal cord is not a feature of human SCI. The usual lesion is one of compression and disruption with haemorrhage. The second and most important aspect of human SCI is to understand that Wallerian degeneration inevitably ensues following disruption of the axon. Wallerian degeneration is progressive and inexorable and unlike the peripheral nervous system CNS axons do not regenerate. The third and more helpful fact is that in the majority (71%) of SCI autopsies a small amount of white matter, myelin and axons, was found to be preserved at the level of injury. Re-activation of these dormant, axons offers the opportunity for improvement of the SCI patient’s neurological status by means of restorative neurology (RN).

Belief in the Body: Philippe Garrel's Le Révélateur and Deleuze

Paragraph ◽  
2008 ◽  
Vol 31 (2) ◽  
pp. 159-172 ◽  
Author(s):  
PATRICK FFRENCH
Keyword(s):  
Nervous System ◽  
The Body ◽  
The Sublime ◽  
The World

In Cinema II Deleuze proposes, via early film theorists, that cinema can realise the potential inherent in art to act directly on the nervous system. Cinema had the ‘sublime’ capacity to shock thought into activity, and awaken the ‘spiritual automaton’ in us through vibrations and affects, rather than representations. Deleuze finds a variant of this argument in the writings of Artaud on cinema, in which film forces the realisation of an impotence at the heart of thought. Deleuze then proposes that the only response to this impotence is belief in the connection between man and the world, as expressed and realised in a corporeal cinema of gestures, the prime example of which, in his view, is the work of Philippe Garrel. I will address Garrel's film Le Révélateur in relation to these propositions, focussing also on how the film works primarily at the level of sensory and gestural dynamics, rather than narrative or representation.

scholarly journals Early development and embryology of the platypus

1998 ◽  
Vol 353 (1372) ◽  
pp. 1101-1114 ◽  
Author(s):  
R. Leon Hughes ◽  
Leslie S. Hall
Keyword(s):  
Nervous System ◽  
Early Development ◽  
Developmental Stages ◽  
Major Axis ◽  
Primitive Streak ◽  
Acute Angle ◽  
Yolk Sac ◽  
The Body ◽  
Main Body ◽  
New Born

Information on the pre–hatching development of the platypus, Ornithorhynchus anatinus , is reliant on a small number of specimens, whose precise age is unknown. Material collected for J. P. Hill and now housed in the Hubrecht International Embryological Laboratory, Utrecht, contributes a major source of specimens. This paper presents new observations on developmental stages from the Hill collection, which allow for a more complete description of pre–hatching development. A feature of the pre–embryonic development of the platypus is the incomplete meroblastic cleavage. A column of fine yolk spheres extends from beneath the embryonic blastodisc towards the centre of a yolky vitellus, as seen in birds. The major expansion of extra–embryonic membranes occurs after the formation of the primitive streak. The primitive streak develops within an embryonal area as part of the superficial wall of the yolk–sac, a feature also shared with marsupials, birds and reptiles. The full–term, subspheroidal, intrauterine egg of the platypus has a major axis of about 17 mm and contains a flat, 19 to 20 somite, neurula–stage embryo which has prominent trigeminal ganglion primordia. The embryo at this stage is in a period of rapid modelling of the major early organ primordia of the nervous system, cardiovascular system, excretory system, and somite–derived components of the body wall. Soon after laying, five primary brain vesicles are present, the trigeminal ganglia CN5 as well as CN7, CN8, CN9, CN10, CN11 and CN12 are well developed. The alimentary system has an expanded stomach, pancreatic primordia and a gall bladder. Mesonephric tubules are associated with patent mesonephric ducts, which empty laterally into the cloaca. Extra–embryonic membranes at this stage show an extensive chorioamniotic connection that extends through the greater part of the caudal half of fused amniotic folds. The vascularized yolk–sac consists of a superficial yolk–sac omphalopleura and a deep yolk–sac splanchnopleure. The non–vascularized yolk–sac comprises one–quarter of the aboembryonal pole. Some distinctive monotreme features have developed by the mid–incubation period. The head is bent at an acute angle to the main body axis. The blunt upturned snout marks the site of the future oscaruncle and on the maxilla there is a median primordial papilla representing the egg tooth. The eye is open with a partly pigmented retinal ring. The forelimbs have partly separated digits, and the hindfeet are paddles. Just before hatching the upturned snout contains an oscaruncle and a sharp recurved median egg tooth. Forelimbs are pronated with separate digits possessing claw primordia. Portions of the highly vascularized extra–embryonic membranes are attached to the umbilical region and the flattened vesicular allantois has a distal region fused with the chorion. Prominent features of the hatchling are the presence of a bluntly conical oscaruncle and a translucent, horn–like egg tooth. These structures are thought to enable the hatchling to extricate itself from the egg shell. At hatching, the forelimbs exhibit clawed digits and are capable of digitopalmar prehension. Hindlimbs are still paddles with digital rays. A prominent yolk–sac navel is present. The newly hatched platypus has an external form similar to that of a new–born marsupial. The early development of the platypus has many major differences to the developmental sequence for humans, which has been categorized by the use of Carnegie Stages. The rate of somitogenesis of the platypus is faster in relation to the central nervous system morphogenesis than seen in humans, and the size of the early platypus embryonal area is massive in relation to that of humans. The unique morphology and function of extra–embryonic membranes in the platypus defies comparative staging with human development. Structures adapted for altricial survival of the platypus hatchling require the acquisition of functional competence at an earlier stage of organogenesis than seen in eutherians, although they are reminiscent of those found in new–born marsupials.

Sign in / Sign up

Export Citation Format

Share Document