SK_SU2015_DCN

SK_SU2015_DCN#

class braincell.channel.SK_SU2015_DCN(size, g_max=Quantity(0.01, 'mS / cm^2'), qdeltat=1.0, name=None)#

Small-conductance calcium-activated potassium current, DCN.

Template-based import of SK_SU15_DCN.mod, part of the deep cerebellar nuclei (DCN) neuron model of (Sudhakar et al., 2015) [2].

\[\begin{split}\begin{aligned} I_{SK} &= g_{\mathrm{max}} \, z \, (E_K - V) \\ \frac{dz}{dt} &= \frac{z_{\infty} - z}{\tau_z} \\ z_{\infty} &= \frac{[\mathrm{Ca}]_i^4} {[\mathrm{Ca}]_i^4 + 8.1 \times 10^{-15}} \\ \tau_z &= \begin{cases} 1 - 186.67 \, [\mathrm{Ca}]_i & [\mathrm{Ca}]_i < 0.005~\mathrm{mM} \\ 0.0667 & [\mathrm{Ca}]_i \geq 0.005~\mathrm{mM} \end{cases} \end{aligned}\end{split}\]

where \([\mathrm{Ca}]_i\) is expressed in mM and \(\tau_z\) in ms before being divided by qdeltat.

Parameters:

  • size (int | Sequence[int] | integer | Sequence[integer]) – Channel state shape.

  • g_max (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Maximal conductance density, default 0.01 mS/cm2.

  • qdeltat (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Divisor applied to \(\tau_z\) after evaluation, default 1.0.

  • name (str | None) – Optional channel name.

Notes

Ported from SK_SU15_DCN.mod. The mechanism name SK and the rate constants above appear only in the deposited NMODL code, not in the body of the Sudhakar et al. (2015) article, which documents the DCN model as reused from a previously published model rather than reprinting per-mechanism constants. The origin chain, reached only through the .mod file’s own credit line (not through either paper’s text): kinetics from the deep cerebellar nucleus model of Steuber et al. (2011) [1], translated from GENESIS to NEURON by Luthman et al. (2011), and used unchanged in Sudhakar et al. (2015) [2]. Luthman et al. (2011) does not appear anywhere in the Sudhakar et al. (2015) text and is recorded here only as the translation step, not as a numbered reference.

Import deviation, distinct from the code’s own branch. The upstream .mod file tabulated zinf and tauz over a clamped cai range of [0, 0.01] mM via a NEURON TABLE statement; BrainCell evaluates the closed-form expressions above on every call instead. This former-TABLE clamp is a separate fact from the [Ca]_i < 0.005 mM branch inside \(\tau_z\) itself, which is the model’s own piecewise definition and is not an artefact of removing the table.

References

current_owner_type#

alias of Potassium