## Search found 11 matches

Mon Aug 03, 2020 4:50 pm
Forum: NEURON + Python
Topic: Ephaptic coupling of Axons
Replies: 1
Views: 572

### Ephaptic coupling of Axons

Hi, Does NEURON have any way of modelling ephaptic coupling of Axons? I've an axon modelled : HH (for nodes of ranvier)----------(passive cable for myelin)------------HH. Is there a way to run them in parallel? I am trying to build a simple parallel model assuming that all the nodes of ranvier are l...
Tue Jul 28, 2020 9:02 am
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

This is so helpful! Can't thank you enough. Really, thank you for all your help. I think I'm getting there now.
One final question (...I hope, you've helped me enough). What effect does nseg have on the length of the internode?
Mon Jul 27, 2020 1:18 pm
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Update:
I think I understand how the function l2a() works.
Still baffled about the why. No clue why or the how of fac() function.
Sat Jul 25, 2020 8:38 am
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Yeah, sorry about the variable names, I am just trying to make it work, not the best names for them. I'll try to document them well once the basics work. the default parameters of NEURON's hh mechanism should be sufficient Gotcha! I changed it to just hh and it works the same, thanks. The model's ot...
Thu Jul 23, 2020 1:29 pm
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Two nodes separated by a lot of internodes. You'll never get a propagating action potential. Would having the structure like N----I--------N and then vary the length of the internode be a better option? I tried with internode lengths from 1mm to 15mm and the signal seems to be dropping off after 10...
Wed Jul 22, 2020 11:56 am
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Sorry to bombard you with questions. I've the following code (adapted from cable.hoc implementation of Brill et al). class BallAndStick: def __init__(self, gid, myelin_length): self._gid = gid self.ml = myelin_length self._setup_morphology() self._setup_biophysics() def _setup_morphology(self): self...
Tue Jul 21, 2020 2:03 pm
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

I tried with the Ra formula and I am not getting any spikes in the ball and stick model, I might be doing something wrong. I just set the cm and Ra as you described, is there more to it?
Tue Jul 21, 2020 5:33 am
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Is that N-I-N-I-I-I-...-I-N-I-N (i.e. 4 nodes and a bunch of internodes? Something like that: N-I-I-I-I-......-I-I-N but you need to know diam in order to calculate gm. And you don't know diam. Really sorry, my bad. My prof has tested out the parameters on SPICE model and I am meant to follow that....
Mon Jul 20, 2020 7:20 pm
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

There is actually an existing literature on the effects of internode length on spike propagation. The key papers are Brill et al. Conduction velocity and spike configuration in myelinated fibres: computed dependence on internode distance. Journal of Neurology, Neurosurgery, and Psychiatry 40:769-77...
Mon Jul 20, 2020 2:09 pm
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Re: Modelling a chain of HH cell with myelinated axon

Hi Ted, Thanks a lot, that was of great help in understanding what I actually want. To answer some of your questions: You haven't said how many nodes or internodes you want, or what their properties are to be My project is to only observe the effect of myelin length on the action potential. In other...
Mon Jul 20, 2020 7:37 am
Forum: NEURON + Python
Topic: Modelling a chain of HH cell with myelinated axon
Replies: 16
Views: 2240

### Modelling a chain of HH cell with myelinated axon

Hi, I am a Masters student of Computer Science working on a neuroscience project (completely new to neuroscience). My project is to model nodes of Ranvier (following HH cell dynamics) with myelinated axons to observe the effects of length of the myelin sheath. I am trying to use NEURON+Python for th...