calcium spikes

[ecchiang]

I'm trying to build a model of a neuron to resemble the firing propertieis of a cell I've recorded from. I'm using mod files from various publications. Why is it that I can have a cell with no sodium channels but still have spikes that resemble sodium spikes. I'm pretty sure its the calcium channel causing these spikes but they don't really resemble calcium spikes since theyappear as fast as sodium spikes. How can I make a voltage gated calcium channel that doesn't produce spikes? (using m_inf/n_inf and taus).

Thanks!

[ted]

Why is it that I can have a cell with no sodium channels but still have spikes that resemble sodium spikes.

You're an experimentalist, so pretend you're experimenting on a cell. What experiments
would you do to discover what ionic currents are responsible for a spike? What happens
to the spikes if you change ionic concentrations or equilibrium potentials? What happens if
you block channels or change the expression (upregulate or downregulate) of channels?
Would it be helpful to know the actual time courses of the ionic currents and their underlying
conductances?

How can I make a voltage gated calcium channel that doesn't produce spikes? (using m_inf/n_inf and taus)['/quote]
A premature question at this point. Wait until you know what's responsible for the spikes that
the model is producing. And why make one, when there are many in ModelDB to examine?
Finally, don't forget that you can always build one, based on published parameters,
with the ChannelBuilder--and maybe do a better job than somebody else did with their
(possibly sloppy) NMODL code.