// singlecompartmen--an mimic nucleated patch to test properties of inserted soidum channel
//------------------------------------------------------------------------
strdef neuron_name
neuron_name = "scp"
create soma
soma {
nseg = 10
diam = 10
L = 10
//-------------------Hou Han 081003 -------------------------------
// Notice that the time course of sodium channel depends on some external parameters,
// like:
// 1. celsius (global temperature, influences the most heavily on the time course as shown below)
// since we check it with a singlecompartment model, properties of the cell should also be involved:
// 2. cm (membrane capacity, the first term "cm * dV/dt" in HH equation, doesn't act on CHANNEL but on CELL)
// Ideally, the term "dV/dt" should equal 0 in the V-clamp case (Hodgkin and Huxley,1952),
// but however, NEURON treats all kinds of CLAMPs by a uniform method of solving the whole
// HH equation without these simplifications, so the term "cm * dV/dt" could have a strong
// effect on the time course of the membrane, as well as of the sodium channel. For example,
// setting cm = 100 results in an obvious distortion of the soma.v(0.5) and soma.gna.
// 3. Ra (intracellular resistance, little effect on the time course but a little on the amplitude)
// Ra is crucial in those propagation cases, but here (single section, non-propagation case) it just controls
// the "leakage" of channel current to the nearby cytoplasm. So its influence is limited.
//
// Paradoxically, in the NEURON environment which was designed for neurons rather than channels, it is
// unavoidable that the properties of the "simglecompartment" which we put the channels in will influence
// the properties of the channels which we really care about. So I suggest setting CM = 0 AND RA=INFINITE for the
// exclusivity of the channels' properties which reflects the perfection of the mimic single-channel recording.
//
// ( Fortunately, however, the activation and the inactivation KINETICS are determined only
// by the internal factors all defined in the .mod file. )
//-----------------------------------------------------------------
//---------------------------Hou Han's ---------------------------------
celsius=37 // TEMPERATURE is crucial whenever time course is concerned !!
// near Line 129 of na.mod: " tadj = q10^((celsius - temp)/10)
// mtau = 1/tadj/(a+b) "
// Greg's tadj = 2.3^((37-23)/10)= 2.3^1.4
// default tadj = 2.3^((6.5-23)/10) =2.3^(-1.65)
// difference in mtau = 2.3^3.05 = 12.7 times!!
Ra=10000000000000000000000 // see the comments above
cm=0 // see the comments above
//-------------------------------------------------------------------
//---------------------------Greg's------------------------
// celsius=37
// Ra=100
// cm=0.9
//---------------------------------------------------------
//----------- former settings of NEURON by default---------
// celsius=6.5
// Ra=35.4
// cm=1
//---------------------------------------------------------
}
insert na16
insert na12
insert na