Search found 29 matches

by mganguly
Sun May 28, 2017 11:16 am
Forum: Other questions
Topic: Changing resistivity over axon length
Replies: 3
Views: 4896

Re: Changing resistivity over axon length

Thanks for the reply.

What if I use an unmyelinated axon and instead of varying properties over sections, I aim to vary properties over segments ? Or should I use the distance function in that case ?

Mohit
by mganguly
Fri May 26, 2017 6:32 pm
Forum: Other questions
Topic: Changing resistivity over axon length
Replies: 3
Views: 4896

Changing resistivity over axon length

Hi, I understand resistivity is a section variable and is constant over an entire section. https://www.neuron.yale.edu/neuron/static/docs/help/neuron/neuron/geometry.html#Ra I wanted to know if its possible to make resistivity dependent on the axon length. Eg: If an axon has 500 nodes, the first 250...
by mganguly
Fri Apr 14, 2017 8:59 pm
Forum: Other questions
Topic: 'connect' function in NEURON
Replies: 3
Views: 4936

Re: 'connect' function in NEURON

Hi,

I was recently thinking about it again. In what way does the connect affects the electrical boundary between the two sections ?

Mohit
by mganguly
Thu Mar 30, 2017 10:56 am
Forum: Other questions
Topic: Dynamic clamp
Replies: 0
Views: 8402

Dynamic clamp

Hi, I am trying to set up a dynamic clamp by importing a series of time varying stimulating currents as a matrix and playing them in VecStim.play. On plotting the stimulation currents, I get a plot consisting of all zeros. Here is the code snippet I am using in Python. current = np.genfromtxt('i.csv...
by mganguly
Wed Sep 14, 2016 5:15 pm
Forum: Other questions
Topic: Resting Membrane Potential
Replies: 2
Views: 5248

Re: Resting Membrane Potential

Thanks a lot for the reply.

Mohit
by mganguly
Tue Sep 06, 2016 3:17 pm
Forum: Other questions
Topic: Resting Membrane Potential
Replies: 2
Views: 5248

Resting Membrane Potential

Hi ! I am trying to model the behaviour of squid giant axon at different temperature and using the results of this paper as a basis. (http://www.ncbi.nlm.nih.gov/pubmed/11081712). It reports the value of ~57mV at 5 oC and about -59 mV at 15oC. These values are different (more positive) than the stan...
by mganguly
Mon Jul 25, 2016 10:53 am
Forum: Other questions
Topic: Changng diameter of squid giant axon
Replies: 3
Views: 4936

Re: Changng diameter of squid giant axon

Hi ! Thanks for the reply. I just ran a quick and dirty simulation. It works for the standard HH model. However, I am working with a model where I change the maximum conductances (to both Na and K ions) with temperature. However, as I keep reducing axon diameter, I start getting spontaneous activity...
by mganguly
Sun Jul 24, 2016 4:24 pm
Forum: Other questions
Topic: Changng diameter of squid giant axon
Replies: 3
Views: 4936

Changng diameter of squid giant axon

Hi ! I want to ask a confirmation question. If I change the diameter of the axon (reduce it 10 times) in a squid giant axon model, do I need to change the maximum ionic conductance (gNabar, gKbar) accordingly. I would assume not, since the units of maximum conductance are in S/cm2 and would be taken...
by mganguly
Fri May 20, 2016 8:29 pm
Forum: Other questions
Topic: USe ko and ki in .mod file
Replies: 6
Views: 3533

Re: USe ko and ki in .mod file

Thanks for the response.

Mohit
by mganguly
Fri May 20, 2016 12:04 pm
Forum: Other questions
Topic: USe ko and ki in .mod file
Replies: 6
Views: 3533

Re: USe ko and ki in .mod file

Great ! That solved the modlunit issue. I am just curious, what does the symbol "?" mean in the .mod file? Like '? interface', or '? currents' etc ?

Thanks,

Mohit
by mganguly
Thu May 19, 2016 3:10 pm
Forum: Other questions
Topic: USe ko and ki in .mod file
Replies: 6
Views: 3533

Re: USe ko and ki in .mod file

Thanks for your reply. Indeed, there was an error. Ik should be ik = gk*pow(n,4)*(v)*(exp(v/24)-ko/ki)/(exp(v/24)-1) where v is the membrane voltage and ko is the external potassium concentration (in the periaxonal space). I modified the USEION statement to USEION k READ ki,ko WRITE ik. The mechanis...
by mganguly
Wed May 18, 2016 6:24 pm
Forum: Other questions
Topic: USe ko and ki in .mod file
Replies: 6
Views: 3533

USe ko and ki in .mod file

Hi I am trying to reproduce the results of the paper " Excitability of the squid giant axon revisited. J Clay (1998)" (http://www.ncbi.nlm.nih.gov/pubmed/9705477). It has a modified version of the K current where Ik = gk*n^4*V*[exp(v/24)-ks/ki]/[exp(v/24)-1], where ks is the potassium concentration ...
by mganguly
Thu Apr 07, 2016 3:32 pm
Forum: Other questions
Topic: Sangrey Model: Gating current
Replies: 1
Views: 990

Sangrey Model: Gating current

I am trying to reproduce the results of the Sangrey et. al. 2004 paper (Analysis of the Optimal Channel Density of the Squid Giant Axon Using a Reparametrized Hodgkin-Huxley Model). In addition to changing the exponent of potassium activation factor n from 4 to 6, they also incorporated a gating cur...
by mganguly
Thu Dec 10, 2015 1:16 pm
Forum: Other questions
Topic: 'connect' function in NEURON
Replies: 3
Views: 4936

'connect' function in NEURON

Hi I am curious to know how does the 'connect' function in neuron work ? How does it account for changes if there are two different mechanisms inserted at either end of the junction between the two sections ( or when there are different parameters assigned eg, gKmax, temperature etc) Thanks, Mohit
by mganguly
Wed Sep 30, 2015 4:51 pm
Forum: Other questions
Topic: Conductance values in passive mechanism
Replies: 3
Views: 1517

Re: Conductance values in passive mechanism

Hi
I am not sure about this but off the top of my head, the conductance in the passive mechanism consists of the leak conductance from the HH mechanism plus the minor conductance from the movement of non specific ions.

Mohit