scholarly journals Rapid pressure changes and surface displacements in the squid giant axon associated with production of action potentials.

1982 ◽  
Vol 32 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Ichiji TASAKI ◽  
Kunihiko IWASA
Keyword(s):  
Action Potentials ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Surface Displacements ◽  
Pressure Changes ◽  
Rapid Pressure

Membrane action potentials from the squid giant axon

1940 ◽  
Vol 15 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Howard J. Curtis ◽  
Kenneth S. Cole
Keyword(s):  
Action Potentials ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Membrane Action

scholarly journals Stability Analysis of FitzHugh-Nagumo with Smooth Periodic Forcing

2012 ◽  
Vol 1 (2) ◽  
pp. 1-10
Author(s):  
Tyler James Massaro ◽  
Benjamin F. Esham
Keyword(s):  
Stability Analysis ◽  
Lyapunov Exponent ◽  
Action Potentials ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Phase Portraits ◽  
System Of Differential Equations ◽  
Neuronal Dynamics ◽  
Periodic Forcing ◽  
Differential Model

Alan Lloyd Hodgkin and Andrew Huxley received the 1963 Nobel Prize in Physiology for their work describing the propagation of action potentials in the squid giant axon.  Major analysis of their system of differential equations was performed by Richard FitzHugh, and later by Jin-Ichi Nagumo who created a tunnel diode circuit based upon FitzHugh’s work.  The resulting differential model, known as the FitzHugh-Nagumo (FH-N) oscillator, represents a simplification of the Hodgkin-Huxley (H-H) model, but still replicates the original neuronal dynamics (Izhikevich, 2010).  We begin by providing a thorough grounding in the physiology behind the equations, then continue by introducing some of the results established by Kostova et al. for FH-N without forcing (Kostova et al., 2004).  Finally, this sets up our own exploration into stimulating the system with smooth periodic forcing.  Subsequent quantification of the chaotic phase portraits using a Lyapunov exponent are discussed, as well as the relevance of these results to electrocardiography.

Differential conduction at axonal bifurcations. I. Effect of electrotonic length

1988 ◽  
Vol 59 (4) ◽  
pp. 1277-1285 ◽  
Author(s):  
N. Stockbridge ◽  
L. L. Stockbridge
Keyword(s):  
Nervous System ◽  
Action Potentials ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Membrane Properties ◽  
General Phenomenon ◽  
Frequency Dependent ◽  
Daughter Branch

1. Frequency-dependent differential conduction of action potentials into one daughter branch of the squid giant axon is demonstrated. 2. This differential conduction arises from differences in the electrotonic length of the daughters, rather than inhomogeneities in membrane properties. 3. It may therefore be a more general phenomenon in the nervous system than is differential conduction which does depend upon membrane inhomogeneities.

Neurofilaments and Paired Helical Filaments

1985 ◽  
Vol 43 ◽  
pp. 740-743
Author(s):  
J. Metuzals
Keyword(s):  
Animal Model ◽  
Posttranslational Modifications ◽  
Posttranslational Modification ◽  
Giant Axon ◽  
Paired Helical Filaments ◽  
Squid Giant Axon ◽  
In Vitro Experiments ◽  
Thin Sections ◽  
Structural Relationships

It has been demonstrated that the neurofibrillary tangles in biopsies of Alzheimer patients, composed of typical paired helical filaments (PHF), consist also of typical neurofilaments (NF) and 15nm wide filaments. Close structural relationships, and even continuity between NF and PHF, have been observed. In this paper, such relationships are investigated from the standpoint that the PHF are formed through posttranslational modifications of NF. To investigate the validity of the posttranslational modification hypothesis of PHF formation, we have identified in thin sections from frontal lobe biopsies of Alzheimer patients all existing conformations of NF and PHF and ordered these conformations in a hypothetical sequence. However, only experiments with animal model preparations will prove or disprove the validity of the interpretations of static structural observations made on patients. For this purpose, the results of in vitro experiments with the squid giant axon preparations are compared with those obtained from human patients. This approach is essential in discovering etiological factors of Alzheimer's disease and its early diagnosis.

Injury-induced vesiculation and membrane redistribution in squid giant axon

1990 ◽  
Vol 1023 (3) ◽  
pp. 421-435 ◽  
Author(s):  
Harvey M. Fishman ◽  
Kirti P. Tewari ◽  
Philip G. Stein
Keyword(s):  
Giant Axon ◽  
Squid Giant Axon

Anterograde Transport of Peptide-Conjugated Fluorescent Beads in the Squid Giant Axon Identifies a Zip-Code for the Synapse

2004 ◽  
Vol 207 (2) ◽  
pp. 164-164
Author(s):  
Michael P. Conley ◽  
Marcus K. Jang ◽  
Joseph A. DeGiorgis ◽  
Elaine L. Bearer
Keyword(s):  
Giant Axon ◽  
Squid Giant Axon ◽  
Anterograde Transport ◽  
Fluorescent Beads ◽  
Zip Code

scholarly journals Air Movement in Snow Due to Windpumping

1989 ◽  
Vol 35 (120) ◽  
pp. 209-213 ◽  
Author(s):  
S.C. Colbeck
Keyword(s):  
Pore Space ◽  
Barometric Pressure ◽  
Surface Flows ◽  
Wind Speeds ◽  
Compression And Expansion ◽  
Strong Winds ◽  
Pressure Changes ◽  
Low Amplitude ◽  
Pressure Perturbations ◽  
Rapid Pressure

Abstract Strong winds can disrupt the thermal regime in seasonal snow because of the variation in surface pressure associated with surface features like dunes and ripples. Topographical features of shorter wavelengths produce stronger surface flows, but the flow decays rapidly with depth. Longer-wavelength features produce weaker surface flows but the flow decays more slowly with depth. The flow may only be strong enough to disrupt the temperature field for features of wavelengths on the scale of meters or tens of meters at wind speeds of 10 m/s or more. Other possible causes of windpumping have been examined but they do not appear to be as significant. Rapid pressure perturbations due to turbulence produce very little displacement of the air because of the high frequency and low amplitude. Barometric pressure changes cause compression and expansion of the air in the pore space, but the rate is too low to have much effect.

Preliminary observations on escape swimming and giant neurons in Aglantha digitale (Hydromedusae: Trachylina)

1980 ◽  
Vol 58 (4) ◽  
pp. 549-552 ◽  
Author(s):  
S. Donaldson ◽  
G. O. Mackie ◽  
A. Roberts
Keyword(s):  
Action Potentials ◽  
Giant Axon ◽  
Synaptic Delay ◽  
Giant Axons ◽  
A Value ◽  
Giant Synapses ◽  
Run Up

Aglantha can swim in two ways, one of which, fast swimming, is evoked by contact with predators and serves for escape. The response consists of two or three violent contractions of which the first propels the animal a distance equivalent to five body lengths. Peak velocities in the range 0.3–0.4 m s−1 were measured. Drag is reduced by contraction of the tentacles.Coordination of escape swimming and tentacle contraction is achieved by a system of giant axons. A giant axon runs down each tentacle; action potentials in these elements show a one-for-one correspondence with potentials recorded from a ring-shaped axon lying in the margin near the tentacle bases. The ring giant synapses with eight motor giants which run up the subumbrella innervating the swimming muscles.Conduction velocities in the giant axons may be as high as 4.0 m s−1 in the case of the largest (40 μm diameter) axons. A value of 1.6 ms was obtained for minimum synaptic delay between the ring and motor giant axons.

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