Kca3p1_MA2020_GoC

Kca3p1_MA2020_GoC#

class braincell.channel.Kca3p1_MA2020_GoC(size, g_max=Quantity(120., 'mS / cm^2'), q10_base=3.0, temp=Quantity(295.15, 'K'), name=None)#

Kca3.1 (IK) calcium-activated K current, Golgi cell.

Template-based import of Kca3p1_MA20_GoC.mod, part of the cerebellar Golgi cell model of (Masoli et al., 2020) [4]. A single gate whose forward rate factors into an independent voltage-dependent term and a piecewise calcium-dependent term.

\[\begin{split}\begin{aligned} I &= g_{\mathrm{max}} \, p \, (E_K - V) \\ \frac{dp}{dt} &= \frac{p_{\infty} - p}{\tau_p} \\ p_{\infty} &= \frac{p_{\alpha}}{p_{\alpha} + p_{\beta}}, \quad \tau_p = \frac{1}{p_{\alpha} + p_{\beta}} \\ p_{\alpha} &= \exp\!\left(\frac{V' + 70}{27}\right) \cdot Y_{\mathrm{concdep}} \\ Y_{\mathrm{concdep}} &= \begin{cases} \dfrac{500 \times 0.0013} {\operatorname{exprel}\!\left(\dfrac{0.015 - [\mathrm{Ca}]_i}{0.0013}\right)} & [\mathrm{Ca}]_i < 0.01~\mathrm{mM} \\[6pt] \dfrac{500 \times 0.005}{\exp(0.005 / 0.0013) - 1} & [\mathrm{Ca}]_i \geq 0.01~\mathrm{mM} \end{cases} \\ p_{\beta} &= 0.05 \end{aligned}\end{split}\]

where \(V' = V / \mathrm{mV}\), \([\mathrm{Ca}]_i\) is expressed in mM, and \(\operatorname{exprel}(y) = (e^y - 1) / y\) (evaluated without the removable singularity at \(y = 0\)).

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 120.0 mS/cm2.

  • q10_base (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Accepted but not used; see Notes. Default 3.0.

  • temp (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Accepted but not used; see Notes. Default 22 degrees Celsius.

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

See also

Kca3p1_MA2025_BC

Same kinetics, basket-cell model citation.

Kca3p1_MA2024_PC

Same kinetics, Purkinje-cell model citation.

Notes

Ported from Kca3p1_MA20_GoC.mod, whose header credits the implementation to Rubin & Cleland (2006) [1], the parameters to Bhalla & Bower (1993) [2], and the mod file itself to Andrew Davison [3].

``q10_base`` and ``temp`` are accepted but never read. Both are stored on self in __init__ but no method in this class – there is no _phi() here, unlike the Kca2p2_* and Kca1p1_* classes below – references either attribute. This is a discrepancy between the constructor signature and the implemented kinetics; it is documented rather than fixed, and the signature is left unchanged. The same holds for Kca3p1_MA2025_BC and Kca3p1_MA2024_PC, whose __init__ is inherited unchanged from this class.

p_beta = 0.05 is a fixed internal constant assigned in __init__, not a constructor parameter.

Import deviation, distinct from the code’s own branch. The upstream .mod file tabulated Yvdep and Yconcdep via a NEURON TABLE statement over V in [-100, 100] mV and cai clamped to [0, 0.01] mM; BrainCell evaluates the closed-form expressions above on every call instead. This former table clamp happens to share its upper concentration bound (0.01 mM) with the model’s own [Ca]_i < 0.01 mM branch inside \(Y_{\mathrm{concdep}}\), but the two are independent facts: the branch is the model’s own definition, unaffected by table removal; the clamp is a NEURON interpolation-range artefact that no longer applies.

References

current_owner_type#

alias of Potassium