Spatially inhomogeneous density mechanisms?

[espenhgn]

Hi,
I didn't see this pop up in the documentation or list of issues or elsewhere: Are there currently any ways of varying parameters of density mechanisms (g of pas etc.) dependent on location (from place_pwlin, relative location on branch or similar)?

The decor examples shown here https://docs.arbor-sim.org/en/latest/concepts/decor.html?highlight=decor.paint#cablecell-properties for instance imply that one can only define constant densities per region.

Specifically I would like to define a membrane current which parameters depends on some function f(z) where z is location on the z-axis.

Edit: For some motivation: it is well known that densities of certain channels, for instance Ih may display an exponential like dependence on the distance to the soma in pyramidal cells: https://doi.org/10.1523/JNEUROSCI.3664-05.2006

Thanks in advance.

[brenthuisman]

Using arbor.mechanism you can create your own function that varies any range parameter. The documentation is here. Or have you already seen this and is it not what you mean?

[edit] Ah, wait, I think this is not what you mean.

[espenhgn]

No, I didn't think that page described what I wanted :-)

[brenthuisman]

The short answer is: not possible ATM. It is on our TODO, but we discovered we don't have a clear issue for it. If you want, you can make one (you already wrote down clear motivation).

[espenhgn]

Fine, I can create an issue. Thanks.

[thorstenhater]

Hi @espenhgn,

we added this feature under the name 'Inhomogeneous Parameters' (https://docs.arbor-sim.org/en/stable/concepts/decor.html#scaled-mechanisms). Is that closer to what you had in mind?

[espenhgn]

Great, thanks a lot!