Hi,
Thanks a lot for your replies.
Regarding your first question, please note that I took the matlab code from
Izhikevich's book, chapter 8 so that I kept the time variable as is.
The simulated model has reduced many Hodgkin-Huxely-type neuronal models to a
two-dimensional system of ordinary differential equations and can reproduces behavior
of different types of neurons using different values of the parameters ( a, b,
c, d, C .. ).
Finally, I have hyperpolarized the cell using the following code but the model
still generates the results for the tonic firing pattern:
.
.
for i=1:n-1 % forward Euler method
if (i<100)
I(i)=-100;
end;
.
.
Best Regards,
Kamal.
> Date: Fri, 19 Feb 2010 12:06:23 -0500
> From: neur-sci-request from oat.bio.indiana.edu> Subject: Neur-sci Digest, Vol 57, Issue 5
> To: neur-sci from magpie.bio.indiana.edu>> Send Neur-sci mailing list submissions to
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>>> Today's Topics:
>> 1. Thalamocortical Neurons (Kamal J. AbuHassan)
> 2. Re: Thalamocortical Neurons (Bill)
> 3. (no subject) (Dhruba Pathak)
>>> ----------------------------------------------------------------------
>> Message: 1
> Date: Thu, 18 Feb 2010 18:46:53 +0000
> From: "Kamal J. AbuHassan" <kamal.abuhassan from hotmail.com>
> Subject: [Neuroscience] Thalamocortical Neurons
> To: <neur-sci from magpie.bio.indiana.edu>
> Message-ID: <SNT109-W464CE43F8DCD2618D46BC9FB470 from phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>>> Hi,
>> I have started to study Izhikevich's large scale model of mammalian thalamocortical systems, I have tried to simulate the neuronal model : v=(k*(v(i)-vr)*(v(i)-vt)-u(i)+I(i))/C and u=a*(b*(v(i)-vr)-u(i)) using the parameters in fig. 10 of the appendix (for Thalamocortical Neurons: C=200; vr=-60; vt=-50; k=1.6;a=0.1; b=15 or zero depending on v; c=-60; d=10;vpeak=40;) to get the burst firing pattern of Thalamocortical Neurons (see fig.3A of the paper) but the model always generate the results for the tonic firing pattern, I am using the following matlab code from Izhikevich's book, chapter 8:
>> C=200; vr=-60; vt=-50; k=1.6; % parameters used for (TC)
> a=0.1; b=15; c=-60; d=10; %
> vpeak=40; % spike cutoff
> T=1000; tau=1; % time span and step (ms)
> n=round(T/tau); % number of simulation steps
> v=vr*ones(1,n); u=0*v; % initial values
> I=[zeros(1,0.1*n),200*ones(1,0.9*n)];% pulse of input DC current
> for i=1:n-1 % forward Euler method
> if v(i)>=-60
> b=0;
> end;
> v(i+1)=v(i)+tau*(k*(v(i)-vr)*(v(i)-vt)-u(i)+I(i))/C;
> u(i+1)=u(i)+tau*a*(b*(v(i)-vr)-u(i));
> if v(i+1)>=vpeak % a spike is fired!
> v(i)=vpeak; % padding the spike amplitude
> v(i+1)=c; % membrane voltage reset
> u(i+1)=u(i+1)+d; % recovery variable update
> end;
> end;
> plot(tau*(1:n), v); % plot the result
>>> Can you help me please ?
>> Thanks,
> Kamal.
>> _________________________________________________________________
> Hotmail: Trusted email with powerful SPAM protection.
>http://clk.atdmt.com/GBL/go/201469227/direct/01/>> ------------------------------
>> Message: 2
> Date: Thu, 18 Feb 2010 20:28:59 -0800 (PST)
> From: Bill <connelly.bill from gmail.com>
> Subject: [Neuroscience] Re: Thalamocortical Neurons
> To: neur-sci from net.bio.net> Message-ID:
> <f724181c-5086-4df3-93dd-f0d6653bd068 from e19g2000prn.googlegroups.com>
> Content-Type: text/plain; charset=ISO-8859-1
>> Hi Kamal,
>> Hopefully someone else will be able to answer your question better
> than I... I don't know anything about matlab, but I can vaguely write
> stuff for NEURON. But I just had a couple of questions, any maybe when
> you answer them, you might see where you problem is.
>> Firstly... am I right in reading that your time step is 1 ms? That
> hardly seems small enough? I would have thought you needed a time step
> of 10 micro seconds.
>> Secondly, this must just be an integrate and fire neuron? I can't see
> any hodgkin-huxley type channels. Moreover, what is the mechanism for
> generating the "calcium current" needed for the burst firing? I can't
> see one.
>> Finally, you must hyperpolarize a cell to get it to burst, are you
> sure you are hyperpolarizing it?
>> On Feb 19, 7:46 am, "Kamal J. AbuHassan" <kamal.abuhas... from hotmail.com>
> wrote:
> > Hi,
> >
> > I have started to study Izhikevich's large scale model of mammalian thalamocortical systems, I have tried to simulate the neuronal model : v=(k*(v(i)-vr)*(v(i)-vt)-u(i)+I(i))/C and u=a*(b*(v(i)-vr)-u(i)) using the parameters in fig. 10 of the appendix (for Thalamocortical Neurons: C=200; vr=-60; vt=-50; k=1.6;a=0.1; b=15 or zero depending on v; c=-60; d=10;vpeak=40;) to get the burst firing pattern of Thalamocortical Neurons (see fig.3A of the paper) but the model always generate the results for the tonic firing pattern, I am using the following matlab code from Izhikevich's book, chapter 8:
> >
> > C=200; vr=-60; vt=-50; k=1.6; % parameters used for (TC)
> > a=0.1; b=15; c=-60; d=10; %
> > vpeak=40; % spike cutoff
> > T=1000; tau=1; % time span and step (ms)
> > n=round(T/tau); % number of simulation steps
> > v=vr*ones(1,n); u=0*v; % initial values
> > I=[zeros(1,0.1*n),200*ones(1,0.9*n)];% pulse of input DC current
> > for i=1:n-1 % forward Euler method
> > if v(i)>=-60
> > b=0;
> > end;
> > v(i+1)=v(i)+tau*(k*(v(i)-vr)*(v(i)-vt)-u(i)+I(i))/C;
> > u(i+1)=u(i)+tau*a*(b*(v(i)-vr)-u(i));
> > if v(i+1)>=vpeak % a spike is fired!
> > v(i)=vpeak; % padding the spike amplitude
> > v(i+1)=c; % membrane voltage reset
> > u(i+1)=u(i+1)+d; % recovery variable update
> > end;
> > end;
> > plot(tau*(1:n), v); % plot the result
> >
> > Can you help me please ?
> >
> > Thanks,
> > Kamal.
> >
> > _________________________________________________________________
> > Hotmail: Trusted email with powerful SPAM protection.http://clk.atdmt.com/GBL/go/201469227/direct/01/>>>> ------------------------------
>> Message: 3
> Date: Fri, 19 Feb 2010 16:50:56 +0100
> From: Dhruba Pathak <pathakdhruba from gmail.com>
> Subject: [Neuroscience] (no subject)
> To: connelly.bill from gmail.com> Cc: neur-sci from magpie.bio.indiana.edu> Message-ID:
> <9fed4bc61002190750g52513b95ia6cb8b571c2af708 from mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>> Hi,
> I read some where comment that you have suggested for bursting.
>> As I also do not know about the Mat lab program. To my knowledge,
> there are two types of neurons. One produce spontanous bursting while
> other needs stimulus. These stimulus may be depolarizing current or
> some blockers..
>> However, I could not understand the correlation between
> hyperpolarization and bursitng. In fact the hyperpolarization will
> provide homeostatic environment to the cell.
>> I also want to ask you, for example, is there any significance of
> studying the effect of some blocker in particular ion channel which is
> previously blocked by some other agents?
>> Thanks in advance for your comments,
> Sincerely,
> Dhruba Pathak
>>>> ------------------------------
>> _______________________________________________
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