Search found 21 matches

by ChrisR
Mon Nov 14, 2011 4:43 pm
Forum: Parallel NEURON
Topic: Noisy current using normrand?
Replies: 4
Views: 4138

Re: Noisy current using normrand?

Ok, so, after some "scavenger hunting" I think I've figured it out! It's giving my reproduceable noise streams independent of the number of hosts. I've been using information from here: http://www.neuron.yale.edu/neuron/node/60 And this post here: http://www.neuron.yale.edu/phpBB/viewtopic.php?f=31&...
by ChrisR
Sun Nov 13, 2011 6:55 pm
Forum: Parallel NEURON
Topic: Noisy current using normrand?
Replies: 4
Views: 4138

Re: Noisy current using normrand?

Thanks for your reply ted. First of all using the same seed is NOT my goal. It's just a test to see weather I am able to control the random sequence generator. And it seems that its not working. So what actually is the problem here? Inferring from your reply I suspect that the nmod function normrand...
by ChrisR
Fri Nov 11, 2011 9:34 am
Forum: Parallel NEURON
Topic: Noisy current using normrand?
Replies: 4
Views: 4138

Noisy current using normrand?

Hello everybody! I am trying to run a noisy current implementation using normrand in parallel neuron. However, the results I get depend on the number of nodes I am deploying. Therefore I have created a test case in which all random number generators start with the same seed, using a FInitializeHandl...
by ChrisR
Tue Aug 30, 2011 6:29 am
Forum: NEURON + Python
Topic: KCa Channel with TABLE definition in PYTHON
Replies: 2
Views: 1699

Re: KCa Channel with TABLE definition in PYTHON

Ok, I solved it!
Sorry for bothering, I just forgot to put "h.usetable_KCA = 0" as it was done in the .hoc file.
So TABLE is not used. I suppose using tables with two dimensional channels is not possbile, is it?

Christian
by ChrisR
Fri Aug 26, 2011 11:28 am
Forum: NEURON + Python
Topic: KCa Channel with TABLE definition in PYTHON
Replies: 2
Views: 1699

KCa Channel with TABLE definition in PYTHON

Hello everybody! I am currently trying to convert a hoc NEURON model into pyNEURON. However I could not get it to produce the same output as in hoc NEURON from scratch. The one thing preventing identical results was the mod implementation of a Calcium dependent potassium current. I could only get it...
by ChrisR
Wed Jan 06, 2010 6:33 pm
Forum: Other questions
Topic: FATAL COMPUTATION ERROR...
Replies: 8
Views: 3243

Re: FATAL COMPUTATION ERROR...

Ok, I fixed it! However creating Random() inside the function, using declaration localobj r, gave same random values for each cell. Is the seed the same for each creation of Random()? objref r r = new Random() func nnormal() { local v v=r.normal($1, ($2)^2) if( ($1 < 0 && v > 0) || ($1 > 0 && v < 0)...
by ChrisR
Wed Jan 06, 2010 2:50 pm
Forum: Other questions
Topic: FATAL COMPUTATION ERROR...
Replies: 8
Views: 3243

Re: FATAL COMPUTATION ERROR...

Ted, you were right, some values became negative. I tried to write a parameter generator function that draws again if the values are bad, but I always get the following error: /usr/local/nrn/x86_64/bin/nrniv: syntax error in cell_net.hoc near line 8 r = new Random() ^ xopen("cell_net.hoc") execute1(...
by ChrisR
Wed Nov 11, 2009 5:16 pm
Forum: Other questions
Topic: FATAL COMPUTATION ERROR...
Replies: 8
Views: 3243

Re: FATAL COMPUTATION ERROR...

Hello Ted! I am getting a quite similar error: exp(822.449) out of range, returning exp(700) exp(822.449) out of range, returning exp(700) exp(822.449) out of range, returning exp(700) exp(822.449) out of range, returning exp(700) No more errno warnings during this execution Convergence not achieved...
by ChrisR
Wed Oct 28, 2009 9:18 am
Forum: Other questions
Topic: Extracellular Stimulation (2d)
Replies: 39
Views: 20926

Re: Extracellular Stimulation (2d)

Hello everybody! Actually this is the simple case I've started with before messing around with the suction electrode configuration. Maybe this is the configuration you are looking for. So this should work for the myelinated frog axon configuration using the files interpxyz.hoc, setpointers.hoc, calc...
by ChrisR
Thu Oct 22, 2009 1:04 pm
Forum: Other questions
Topic: Extracellular stimulation
Replies: 22
Views: 8943

Re: Extracellular stimulation

Within the cannula both xc and xg must be 0 to satisfy the boundary conditions. so just multiply xraxial of the entire bundle by 1). If I understood you correctly, then extracellular has to be set like this, for sections inside: insert extracellular xraxial=r_e xg=0 xc=0 and outside the canulla?: i...
by ChrisR
Wed Oct 21, 2009 6:59 pm
Forum: Other questions
Topic: Extracellular stimulation
Replies: 22
Views: 8943

Re: Extracellular stimulation

Hello Ted, Is the physical arrangement as diagrammed here? Yes, it is. I've read Bokil et al. but I think since the vestibular nerves are myelinated with ratio rd (fiber diammeter / axon diameter) = 1.5, leading to a beta (ratio of extracellular to intracellular space) = (1.5^2 - 1^2)/(1^2) = 1.25, ...
by ChrisR
Tue Oct 20, 2009 2:54 pm
Forum: Other questions
Topic: Extracellular stimulation
Replies: 22
Views: 8943

Re: Extracellular stimulation

Yes, you are right, the canulla has pretty much the same inner diameter as the nerve bundle.
The method section states: "current pulses were applied across individually adjusted suction electrodes (diameter, 120-150 um)"
by ChrisR
Mon Oct 19, 2009 5:47 pm
Forum: Other questions
Topic: Extracellular stimulation
Replies: 22
Views: 8943

Re: Extracellular stimulation

Ok, now I get it. Thanks! I am currently working on a quite difficult s(t)imulation, would be great If you could give me some advice. I want to replicate data obtained via stimulation with a suction electrode. Vestibular nerve fiber bundles are separately sucked inside (~500 um of nerve inside elect...
by ChrisR
Wed Oct 14, 2009 3:15 pm
Forum: Other questions
Topic: Extracellular stimulation
Replies: 22
Views: 8943

Extracellular stimulation

Hello Ted! I am trying to create a myelinated axon model with extracellular stimulation. To start I took your example scripts (http://www.neuron.yale.edu/ftp/ted/neuron/extracellular_stim_and_rec.zip) and tried to excite a single passive node with the following code: load_file("nrngui.hoc") tstop=3 ...
by ChrisR
Tue Mar 03, 2009 4:05 pm
Forum: Other questions
Topic: Questions on Linear Circuit Builder
Replies: 8
Views: 4217

Questions on Linear Circuit Builder

Hi All! I have two questions: Is it possible to combine a hoc neuron model with a linear circuit from the Linear Circuit Builder to create a hoc file that can be run by a script? I don't see how .ses and the normal hoc configuration plays together. How can I play a current from an external file into...