mechanisms writing ionic concentration

[along82]

Hi, ted
It is stated in a NEURON paper: expanding neuron's repertoire of mechanisms with nmodl
page 26
that: no ionic concentration should be written by more than one mechanism
, which mean that all processes which could affect specific ionic concentration should only be expressed as one mechanism in one .mod file, is is right?
So, we know NEURON could keep track with ica and automatically adds up all sub component of ica by using WRITE ica, but why does NEURON implement a different tragedy in processing concentration?

[ted]

It is stated in a NEURON paper: expanding neuron's repertoire of mechanisms with nmodl
page 26
that: no ionic concentration should be written by more than one mechanism

True. For ionic species x, in any given compartment, there should only be one mechanism that can WRITE the concentration of x.

which mean that all processes which could affect specific ionic concentration should only be expressed as one mechanism in one .mod file

Be careful, now. Remember what George Orwell said:
" . . . the slovenliness of our language makes it easier for us to have foolish thoughts."
He was writing about politics, but it is more generally applicable.
For any given compartment, only one mechanism may contain the statement
USEION x . . . WRITE xi or xo
but there can be many mechanisms that
USEION x . . . WRITE ix
So there can be many mechanisms that may affect ionic concentration, but only one that
actually computes the value of ionic concentration in a given compartment..

So, we know NEURON could keep track with ica and automatically adds up all sub component of ica by using WRITE ica, but why does NEURON implement a different tragedy in processing concentration?

It's a natural consequence of the notion of conservation of mass, which is described by
the equation
rate of change of amount of substance x = sum of all influx of x - sum of all efflux of x
No matter how many different terms are on the right hand side, there is still only one
equation.

By the way, you mean "strategy."