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Eye (London. 1987)
London SUMMARY The conduction properties of central demyelinated and remyelinated axons are discussed, and related to the expression of symptoms in central demyelinating disease. ... The mechanisms underlying the block and restoration of conduction in segmentally demyelinated axons are described, together with the range of deficits expressed by the conducting axons. ... The factors underlying the increase in RPT have recently been studied using computer simulations of conduction along partially demyelinated axons.71 Fig. 4 . 4 Record showing bursts of ascending impu ...doi:10.1038/eye.1994.51 pmid:7958027 fatcat:ajgpyuq4afcgxgbpb7oa4ttqku
The effects of temperature (from 20 • C to 42 • C) on action and polarizing electrotonic potentials (nodal and internodal) and their current kinetics were previously studied by us in a simulated case of ... However, the superexcitability period in the CIDP case is followed by a late subexcitability period at 37 • C only and the recovery cycles are with reduced superexcitability and without relative refractory ... the axons are still in the absolute refractory period. ...doi:10.1142/s0219635215500065 pmid:25597276 fatcat:tfmpo327rbcrxe2ktq3w35q3cy
Demyelination of neurons can compromise the communication performance between the cells as the absence of myelin attenuates the action potential propagated through the axonal pathway. ... In this work, we propose a hybrid experimental and simulation model for analyzing the demyelination effects on neuron communication. ... refractory periods. ...doi:10.1109/tnsre.2021.3137350 pmid:34932481 fatcat:nod3vjiqsrdbdavddjtvh65r6y
In that respect, computational modeling is an invaluable tool that could, ultimately, transform how we understand, diagnose, and treat demyelinating diseases. ... By making testable predictions and revealing critical gaps in existing knowledge, such models can help direct research and will provide a rigorous framework in which to integrate new data as they are collected ... to demyelination by making comparisons to the threshold tracking measurements from patients including latencies, refractoriness (the increase in threshold current during the relative refractory period ...doi:10.3390/ijms160921215 pmid:26370960 pmcid:PMC4613250 fatcat:46o2a53afjgfpii76vf6x35cne
In this study, we aimed to present a compact screenbased computer simulation for second year medical students so that they may experience various aspects of peripheral nerve electrophysiology by themselves ... Results: The simulation provides numerical and visual demonstration for various electrophysiological features of nerve cell such as membrane potential development, threshold stimulus, refractoriness, conduction ... Action Potential and Refractoriness In the screen tab called "Action Potential", the change in membrane potential, AP at a Ranvier node is visualized in response to a stimulus. ...doi:10.4236/oalib.1101288 fatcat:s6befdefgrhwdoxja5pbpyuc3q
Sural sensory action potentials were measured in a group of 13 patients with gluten neuropathy before and 12 months after starting a gluten free diet. ... A simulation analysis estimated a maximum lod score of 4.17 at theta=0 and 3.84 at theta=0.05. ...doi:10.1136/jnnp.72.1.127 pmid:11784845 pmcid:PMC1737683 fatcat:jynp3kia4rcbxdu4fy44dp62ki
Tegner axons was longer when measured after an electrical stimulus delivered through the same electrode as the test stimulus than after a propagated action potential. ... This agrees with a previous study of single alpha motor axons in man (Borg 1984). ...
The consequences of such an assumption have been investigated by numerical solution of a well-known set of differential equations describing conduction in a model demyelinated axon. ... It is generally believed that the clinical signs and symptoms in MS are the result of defects of impulse conduction in demyelinated axons of the central nervous system. ... The prediction of this model that the absolute refractory period is increased to approximately 2-5 times normal in a 9000 demyelinated fibre seems in reasonable accord with these observations. ...doi:10.1136/jnnp.37.2.152 pmid:4362242 pmcid:PMC494594 fatcat:3kt63rodp5cong4ukaguc3lzsy
In addition to our simulation study of focal demyelination, we present a justification for a certain geometric W-matrix used in our phenomenological 2019 model. ... It is well known that demyelination associated with multiple sclerosis alters coupling between axons in a diseased nerve tract due to exposure of ion channels. ... Note that the duration of an action potential from our simulation program is about 1 millisecond, but if we include the refractory period, we cannot have action potentials less than about 2 millisecond ...doi:10.1101/2022.03.29.486317 fatcat:ohoat2xmszfk3paics7ogewvky
Computer simulation of action potentials and afterpotentials in mammalian myelinated axons: the case for a lower resistance myelin sheath. Neuroscience 15, 13-31. Bostock, H. & Baker, M. 1988. ... David, G., Barrett, J.N. & Barrett, E.F. action 1992. Evidence that potentials activate an_ internodal potassium conductance in lizard myelinated axons. ] Physiol 445, 277-301. ...
Annals of Neurology
discharges in motor axons substantially exceed the refractory periods under physiologic condition. ... According to computer simulation (Kimura, Sakimura, Machida et al, 1988; Rhee, England, Sumner, 1990), this phenomenon alone can reduce the normal sensory nerve action potential (SNAP) to below 50% in ...doi:10.1002/ana.410160402 pmid:6093680 fatcat:zxnhjgba6fbwpajlywup5yqa3y
The marked increase of refractoriness at short-width stimulus suggests a defect in sodium current which may represent an early, pre-symptomatic pathophysiological change in TTR-FAP. ... The regression models demonstrate that the increase of refractoriness and prolonged relative refractory period are correlated to the disease progression from carriers to patients. ... The study was supported by a grant provided by the Ministry of Science and Technology, Taiwan (103-2321-B-002-037). Author Contributions ...doi:10.1371/journal.pone.0141935 pmid:26529114 pmcid:PMC4631457 fatcat:fjhltiwxsnau3hrz4kiwij2a2q
Nodal architecture was restored and by quantifying these anatomical parameters a computer model was generated that accurately predicted action potential velocity, determined by ex vivo slice recordings ... Stem cell repair shows substantial translational potential for neurological injury, but the mechanisms of action remain unclear. ... Reduced axonal refractoriness in aNPC-transplanted shi/shi CC Previous studies have reported that demyelination leads to an increased axonal refractory period (Nashmi and Fehlings, 2001b) . ...doi:10.1523/jneurosci.1131-13.2013 pmid:23864679 pmcid:PMC3722511 fatcat:fwlwdii6ezdnnno3lour432ydi
Although K ϩ channels were not yet segregated at most of these sites, they were directly involved in action potential generation, reducing duration, and the refractory period. ... A computational model suggested a mechanism for the firing patterns observed, and the results provide a role for K ϩ channels in the prevention of aberrant excitation as myelination proceeds during development ... A, Left, A calculated propagating action potential in a P16 axon as recorded by the simulated suction electrode. Right, After removal of the paranodal /juxtaparanodal K ϩ channel clusters. ...doi:10.1523/jneurosci.19-02-00747.1999 pmid:9880595 fatcat:stohvitsofclvbfwv5c77dd4u4
We show that in Basket cell neurons the design principle being optimized is the ratio between the refractory period of the membrane, and action potential latencies between the initial segment and the synaptic ... A still unsolved fundamental question is what is the relationship between the morphological design principles of individual branching axons and their role in optimizing action potential signaling in the ... Acknowledgements This work was supported by a Swiss National Science Foundation (SNSF) Mobility Fellowship (P2ELP2_168553) to FP. ...doi:10.1038/s41598-018-28527-2 pmid:29992977 pmcid:PMC6041316 fatcat:omhf3lnvjrbkdcrqnsvpb7hmeu
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