Search found 35 matches

by Sun Xiaoqing
Mon Dec 30, 2019 8:58 am
Forum: Getting started
Topic: replicate Waxman's model
Replies: 4
Views: 1861

Re: replicate Waxman's model

I wonder if I use a finer scale (Δx=10um, n_seg=200, compared with Waxman: Δx=200um, n_seg=10),apply Crank-Nicholson method with an integration time increment Δt=5 us, then I should get a more accurate result, is that right?

Thank you.
by Sun Xiaoqing
Thu Dec 26, 2019 10:24 am
Forum: Getting started
Topic: replicate Waxman's model
Replies: 4
Views: 1861

replicate Waxman's model

Merry Chrismas! I'm working on replicating Waxman's model in Waxman, S. G., and Brill, M. H., 1978, Conduction through demyelinated plaques in multiple sclerosis, Computer simulations of facilitation by short internodes, J.Neurol Neurosurg. Psychiatry, 41: 408–416. In Waxman's paper, it is stated th...
by Sun Xiaoqing
Mon Dec 09, 2019 11:04 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

Re: construct a single myelinated axon

Dear ted, I hope all is well with you. It has been a while and I had to pick up this thread since new confusion arose. I'm referring to the model of Moore78: https://senselab.med.yale.edu/ModelDB/showmodel.cshtml?model=9851&file=/moore78/cable.hoc#tabs-2 proc geom() { forsec nodes { // area = 100 um...
by Sun Xiaoqing
Fri Nov 01, 2019 8:16 am
Forum: Getting started
Topic: Spike configuration at internode sections of myelinated axon
Replies: 5
Views: 1626

Re: Spike configuration at internode sections of myelinated axon

Dear Ted,

Thank you so much for the reference book, love the clear explanations. I truly appreciate your help all along!
by Sun Xiaoqing
Wed Oct 30, 2019 7:23 am
Forum: Getting started
Topic: Spike configuration at internode sections of myelinated axon
Replies: 5
Views: 1626

Re: Spike configuration at internode sections of myelinated axon

Dear Ted, I used Shape Plot/Time plot to get the "Spike Waveform". If NEURON uses Cable Equation to calculate voltage potential, when I increased the length of the myelinated section to 20mm, the shape of the "Spike Waveform" got distorted(the time needed for the Spike to get to its maximum value go...
by Sun Xiaoqing
Tue Oct 29, 2019 7:42 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

Re: construct a single myelinated axon

Thank you for your explanation!
by Sun Xiaoqing
Tue Oct 29, 2019 7:41 am
Forum: Getting started
Topic: Spike configuration at internode sections of myelinated axon
Replies: 5
Views: 1626

Spike configuration at internode sections of myelinated axon

Good day, I'm using Moore's Model for myelinated axon: https://senselab.med.yale.edu/ModelDB/ShowModel.cshtml?model=9851#tabs-1 And there's one thing that I didn't understand: Why there are spike configurations at the internode sections? In myelinated sections, there are no transmembrane currents th...
by Sun Xiaoqing
Tue Oct 22, 2019 10:31 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

Re: construct a single myelinated axon

Dear ted, 1. I understood that if myelin sheath is wrapped around the axon, the voltage-gated ion channels in the axolemma couldn't get participated in the process of an AP generation and there're no transmembrane currents. Since no transmembrane currents were involved during Propagation, no spike c...
by Sun Xiaoqing
Tue Oct 22, 2019 4:10 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

Re: construct a single myelinated axon

Thank you for your answer, ted. So if I use extracellular to construct myelinated axon(even with nodes of Ranvier), then I won't be able to see the spike along the myelinated axon at the internode sections(which I tried and the voltage remained to -65mV ), I could only get the AP configuration at th...
by Sun Xiaoqing
Mon Oct 21, 2019 9:23 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

Re: construct a single myelinated axon

Thank you for your reply, Ted. I'm constructing a single myelinated axon without any nodes, just a soma connected to myelinated axon to see how the AP propagates with the change of the diameter. I've looked into the extracellular in the Programmer's reference and I also found there was an extracellu...
by Sun Xiaoqing
Sun Oct 20, 2019 11:39 am
Forum: Getting started
Topic: construct a single myelinated axon
Replies: 10
Views: 2636

construct a single myelinated axon

Good day, I'm trying to construct a single myelinated axon and I got confused with the pas mechanism. 1. If I use the pas mechanism for the biophysical part of the axon, then I'm constructing a myelinated axon? 2. NEURON constructs a myelinated axon by changing its electrical properties, so is there...
by Sun Xiaoqing
Wed Oct 16, 2019 9:09 am
Forum: Getting started
Topic: g_pas
Replies: 1
Views: 942

g_pas

Good day, Sorry for the relatively simple confusion that I have: I know that the g_pas is the density of the specific membrane conductance [S/cm2], but since it is passive conduction, there are no ion channel activities involved, so can I interpret g_pas as the density of conductance of the leakage ...
by Sun Xiaoqing
Wed Oct 02, 2019 9:48 am
Forum: Getting started
Topic: conduction velocity and AP attenuation in demyelinated axon
Replies: 0
Views: 769

conduction velocity and AP attenuation in demyelinated axon

Good day, I've implemented two simple multi-compartment models: 1.A single axon(pas) connected to soma(hh). 2.A single axon(hh) connected to soma(hh). For Model 1, I gave a threshold stimulus that invoked an action potential (AP) and propagated along the axon. I ran a series of simulations of axon w...
by Sun Xiaoqing
Wed Oct 02, 2019 9:28 am
Forum: Getting started
Topic: monitor the attenuation of the peak value of the action potential with distance from the ion channel
Replies: 9
Views: 1191

Re: monitor the attenuation of the peak value of the action potential with distance from the ion channel

Dear Ted, Thank you for introducing me to the introductory course in neurophysiology, although I'm very interested in that course, unfortunately, I'm still in my third year of university and it's such a regret that I can't make it. During the process of discussing with my lecturer, new ideas came ou...
by Sun Xiaoqing
Tue Oct 01, 2019 10:12 am
Forum: Getting started
Topic: monitor the attenuation of the peak value of the action potential with distance from the ion channel
Replies: 9
Views: 1191

Re: monitor the attenuation of the peak value of the action potential with distance from the ion channel

I'm reading this post which I find similar to my case:viewtopic.php?f=15&t=1483
but I have confusion about how to get my half maximum vale of AP during the hyperpolarizing process.
and how to get (x vs Diameter of the axon) and make a plot of it.