Principles of Electrophysiology

Author(s):  
Erwin B. Montgomery

In many ways, post-operative DBS programming is “prescribing electricity” in much the same sense as “prescribing medications.” The principles of pharmacokinetics and pharmacodynamics that guide the rational use of medications find parallels in DBS. Many drugs have their effect by binding to ligand-gated channels, particularly channels that control the flow of electrical charges, in the form of ions across the cell membrane of the neuron in the soma. The binding of drugs to receptors can open the receptor to approximate the normal opening by endogenous neurotransmitters, or to block the channel from opening when endogenous neurotransmitters are released. In the case of DBS, the electrical charges manipulated in the nervous system similarly affect neuronal membrane channels; however, these initially and primarily are voltage gated ionic conductance channels, which are described in detail in this chapter.

Author(s):  
Erwin B. Montgomery

In depolarization to effect neuronal activations,, electrical charges are delivered to the neuron to affect the electrical potential across the neuronal membrane to subsequently affect voltage-gated ionic conductance channels. The orientation of the field of electrical charges to the neuronal membrane is critical. Electrical charges flow from the negative contact to the positive contact. The negative electrostatic charge “pushes” negative charges onto the outer surface of the neuron, which results in depolarization of the neuronal membrane. Neurons near the positive contact will not have negative electrical charges deposited on the outer surface, will not be depolarized, and thus, are not activated. Likewise, neurons whose membranes are oriented parallel to the lines of electrical forces that move electrical charges will not receive the electrical charges and, consequently, will not be activated. The electronics of the DBS systems are designed to control the electrostatic forces so as to control the activations of the nervous system to generate benefit and avoid adverse effects.


1996 ◽  
Vol 109 (7) ◽  
pp. 1749-1757 ◽  
Author(s):  
N. Soussi-Yanicostas ◽  
J.P. Hardelin ◽  
M.M. Arroyo-Jimenez ◽  
O. Ardouin ◽  
R. Legouis ◽  
...  

The KAL gene is responsible for the X-chromosome linked form of Kallmann's syndrome in humans. Upon transfection of CHO cells with a human KAL cDNA, the corresponding encoded protein, KALc, was produced. This protein is N-glycosylated, secreted in the cell culture medium, and is localized at the cell surface. Several lines of evidence indicate that heparan-sulfate chains of proteoglycan(s) are involved in the binding of KALc to the cell membrane. Polyclonal and monoclonal antibodies to the purified KALc were generated. They allowed us to detect and characterize the protein encoded by the KAL gene in the chicken central nervous system at late stages of embryonic development. This protein is synthesized by definite neuronal cell populations including Purkinje cells in the cerebellum, mitral cells in the olfactory bulbs and several subpopulations in the optic tectum and the striatum. The protein, with an approximate molecular mass of 100 kDa, was named anosmin-1 in reference to the deficiency of the sense of smell which characterizes the human disease. Anosmin-1 is likely to be an extracellular matrix component. Since heparin treatment of cell membrane fractions from cerebellum and tectum resulted in the release of the protein, we suggest that one or several heparan-sulfate proteoglycans are involved in the binding of anosmin-1 to the membranes in vivo.


2020 ◽  
Author(s):  
Gianluigi Zangari del Balzo

Abstract Background Stochastic processes leading voltage-gated ion channel dynamics on the nerve cell membrane are a sufficient condition to describe membrane conductance through statistical mechanics of disordered and complex systems.Results Voltage-gated ion channels in the nerve cell membrane are described by the Ising model. Stochastic circuital elements called ”Ising machines” are introduced. Action potentials are described as quasi-particles of a statistical field theory for the Ising system.Conclusions The particle description of action potentials is a new powerful tool to describe the generation and propagation of nerve impulses. We thus have the opportunity to exploit another useful point of view to describe the generation and propagation of nerve impulses, especially when classical electrophysiological models break down. Moreover, the particle description allows us to develop new hardware and software devices based on general and theoretical physics to study neurodegenerative and demyelinating diseases as Multiple Sclerosis and Alzheimer’s disease, even integrated by connectomes. It is also suitable for the study of complex networks, quantum computing, artificial intelligence, machine and deep learning, cryptography, ultra-fast lines for entanglement experiments and many other applications of medical, physical and engineering interest.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Domenico De Berardis ◽  
Stefano Marini ◽  
Monica Piersanti ◽  
Marilde Cavuto ◽  
Giampaolo Perna ◽  
...  

Cholesterol is a core component of the central nervous system, essential for the cell membrane stability and the correct functioning of neurotransmission. It has been observed that cholesterol may be somewhat associated with suicidal behaviours. Therefore, the aim of this paper was to elucidate current facts and views about the role of cholesterol levels in mood disorders. The majority of the studies reviewed in the present paper suggest an interesting relationship between cholesterol (especially lower levels) and suicidality. On the other hand, particularly during the last years, relationships between serum cholesterol and suicidality were doubted on the basis of some recent studies that have not found any correlation. However, the debate on relationships between cholesterol and suicide is open and longitudinal studies on a larger sample of patients are needed to further clarify this important issue.


Bioprinting ◽  
2021 ◽  
pp. 98-118
Author(s):  
Kenneth Douglas

Abstract: This chapter recounts bioprinting studies of skin, bone, skeletal muscle, and neuromuscular junctions. The chapter begins with a study of bioprinted skin designed to enable the creation of skin with a uniform pigmentation. The chapter relates two very different approaches to bioprinted bone: a synthetic bone called hyperelastic bone and a strategy that prints cartilage precursors to bone and then induces the conversion of the cartilage to bone by judicious choice of bioinks. Muscles move bone, and the chapter discusses an investigation of bioprinted skeletal muscle. Finally, the chapter considers an attempt to bioprint a neuromuscular junction, a synapse—a minute gap—of about 20 billionths of a meter between a motor neuron and the cell membrane of a skeletal muscle cell. A motor neuron is a nerve in the central nervous system that sends signals to the muscles of the body.


2006 ◽  
Vol 38 (4) ◽  
pp. 447-451 ◽  
Author(s):  
Michael F Waters ◽  
Natali A Minassian ◽  
Giovanni Stevanin ◽  
Karla P Figueroa ◽  
John P A Bannister ◽  
...  

2006 ◽  
Vol 291 (6) ◽  
pp. L1169-L1176 ◽  
Author(s):  
Candice D. Fike ◽  
Mark R. Kaplowitz ◽  
Yongmei Zhang ◽  
Jane A. Madden

Our purpose was to determine whether smooth muscle cell membrane properties are altered in small pulmonary arteries (SPA) of piglets at an early stage of pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. A microelectrode technique was used to measure smooth muscle cell membrane potential ( Em) in cannulated, pressurized SPA (100- to 300-μm diameter). SPA responses to the voltage-gated K+ (KV) channel antagonist 4-aminopyridine (4-AP) and the KV1 family channel antagonist correolide were measured. Other SPA were used to assess amounts of KV1.2, KV1.5, and KV2.1 (immunoblot technique). Em was more positive in SPA of chronically hypoxic piglets than in SPA of comparable-age control piglets. The magnitude of constriction elicited by either 4-AP or correolide was diminished in SPA from hypoxic piglets. Abundances of KV1.2 were reduced, whereas abundances of both KV1.5 and KV2.1 were unaltered, in SPA from hypoxic piglets. At least partly because of reduced amounts of KV1.2, smooth muscle cell membrane properties are altered such that Em is depolarized and KV channel family function is impaired in SPA of piglets at an early stage of chronic hypoxia-induced pulmonary hypertension.


Author(s):  
Andrea E. Cavanna

Antiepileptic drugs (AEDs) exert their pharmacological properties on both epileptic seizures and behaviour through different mechanisms of action. These include modulation of ion (mainly sodium and calcium) conductance through voltage-gated channels located within the neuronal membrane, as well as facilitation of inhibitory (GABAergic) neurotransmission and inhibition of excitatory (glutamatergic) neurotransmission, resulting in regulation of neuronal excitability.


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