scholarly journals Synaptic actions of peripheral nerve impulses upon Deiters neurones via the climbing fibre afferents

1972 ◽  
Vol 226 (2) ◽  
pp. 311-333 ◽  
Author(s):  
G. I. Allen ◽  
N. H. Sabah ◽  
K. Toyama

While it has been recognized for many years that different limb muscles belonging to the same mammal may have markedly differing contractile characteristics, it is only comparatively recently that it has been demonstrated that these differences depend upon the motor innervation. By appropriately changing the peripheral nerve innervating a mammalian skeletal muscle, it is possible to change dramatically the contractile behaviour of the reinnervated muscle. The manner by which the motor innervation determines the nature of a muscle fibre’s contractile machinery is not completely understood, but it appears that the number and pattern of motor nerve impulses reaching the muscle play an important role. The biochemical changes occurring within muscle fibres whose contractile properties have been modified by altered motor innervation include the synthesis of different contractile proteins.


The purpose of the electrical current delivered during TENS is to generate nerve impulses in peripheral nerve fibres to modulate the flow of nociceptive information and reduce pain. The characteristics of the electrical currents (i.e. stimulating parameters) and physiology at the electrode–skin interface will influence which nerve fibres are excited. Conventional TENS and acupuncture-like TENS are two techniques developed to stimulate different types of nerve fibres. The purpose of this chapter is to overview the biophysical principles of TENS and to explain how these principles have been used to inform clinical practice by covering TENS equipment and the standard TENS device, the electrical characteristics of currents produced by a standard TENS device, lead wires and electrodes, the physiology at the electrode–skin interface including nerve fibre activation by TENS, and TENS techniques used in clinical practice, including conventional TENS and acupuncture-like TENS (AL-TENS).


Author(s):  
Arthur J. Wasserman ◽  
Azam Rizvi ◽  
George Zazanis ◽  
Frederick H. Silver

In cases of peripheral nerve damage the gap between proximal and distal stumps can be closed by suturing the ends together, using a nerve graft, or by nerve tubulization. Suturing allows regeneration but does not prevent formation of painful neuromas which adhere to adjacent tissues. Autografts are not reported to be as good as tubulization and require a second surgical site with additional risks and complications. Tubulization involves implanting a nerve guide tube that will provide a stable environment for axon proliferation while simultaneously preventing formation of fibrous scar tissue. Supplementing tubes with a collagen gel or collagen plus extracellular matrix factors is reported to increase axon proliferation when compared to controls. But there is no information regarding the use of collagen fibers to guide nerve cell migration through a tube. This communication reports ultrastructural observations on rat sciatic nerve regeneration through a silicone nerve stent containing crosslinked collagen fibers.Collagen fibers were prepared as described previously. The fibers were threaded through a silicone tube to form a central plug. One cm segments of sciatic nerve were excised from Sprague Dawley rats. A control group of rats received a silicone tube implant without collagen while an experimental group received the silicone tube containing a collagen fiber plug. At 4 and 6 weeks postoperatively, the implants were removed and fixed in 2.5% glutaraldehyde buffered by 0.1 M cacodylate containing 1.5 mM CaCl2 and balanced by 0.1 M sucrose. The explants were post-fixed in 1% OSO4, block stained in 1% uranyl acetate, dehydrated and embedded in Epon. Axons were counted on montages prepared at a total magnification of 1700x. Montages were viewed through a dissecting microscope. Thin sections were sampled from the proximal, middle and distal regions of regenerating sciatic plugs.


2017 ◽  
Vol 22 (2) ◽  
pp. 3-5
Author(s):  
James B. Talmage ◽  
Jay Blaisdell

Abstract Physicians use a variety of methodologies within the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, to rate nerve injuries depending on the type of injury and location of the nerve. Traumatic injuries that cause impairment to the peripheral or brachial plexus nerves are rated using Section 15.4e, Peripheral Nerve and Brachial Plexus Impairment, for upper extremities and Section 16.4c, Peripheral Nerve Rating Process, for lower extremities. Verifiable nerve lesions that incite the symptoms of complex regional pain syndrome, type II (similar to the former concept of causalgia), also are rated in these sections. Nerve entrapments, which are not isolated traumatic events, are rated using the methodology in Section 15.4f, Entrapment Neuropathy. Type I complex regional pain syndrome is rated using Section 15.5, Complex Regional Pain Syndrome for upper extremities or Section 16.5, Complex Regional Pain Syndrome for lower extremities. The method for grading the sensory and motor deficits is analogous to the method described in previous editions of AMA Guides. Rating the permanent impairment of the peripheral nerves or brachial plexus is similar to the methodology used in the diagnosis-based impairment scheme with the exceptions that the physical examination grade modifier is never used to adjust the default rating and the names of individual nerves or plexus trunks, as opposed to the names of diagnoses, appear in the far left column of the rating grids.


1998 ◽  
Vol 3 (5) ◽  
pp. 1-3
Author(s):  
Richard T. Katz ◽  
Sankar Perraraju

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, offers several categories to describe impairment in the shoulder, including shoulder amputation, abnormal shoulder motion, peripheral nerve disorders, subluxation/dislocation, and joint arthroplasty. This article clarifies appropriate methods for rating shoulder impairment in a specific patient, particularly with reference to the AMA Guides, Section 3.1j, Shoulder, Section 3.1k, Impairment of the Upper Extremity Due to Peripheral Nerve Disorders, and Section 3.1m, Impairment Due to Other Disorders of the Upper Extremity. A table shows shoulder motions and associated degrees of motion and can be used in assessing abnormal range of motion. Assessments of shoulder impairment due to peripheral nerve lesion also requires assessment of sensory loss (or presence of nerve pain) or motor deficits, and these may be categorized to the level of the spinal nerves (C5 to T1). Table 23 is useful regarding impairment from persistent joint subluxation or dislocation, and Table 27 can be helpful in assessing impairment of the upper extremity after arthroplasty of specific bones of joints. Although inter-rater reliability has been reasonably good, the validity of the upper extremity impairment rating has been questioned, and further research in industrial medicine and physical disability is required.


1991 ◽  
Vol 2 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Mark E. Harris ◽  
Suzie C. Tindall

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