HCN2_MA2020_GoC

HCN2_MA2020_GoC#

class braincell.channel.HCN2_MA2020_GoC(size, g_max=Quantity(0.08, 'mS / cm^2'), E=Quantity(-20., 'mV'), temp=Quantity(295.15, 'K'), name=None)#

HCN2 fast/slow h-current imported for the Golgi cell model.

Ports the two-gate NEURON mechanism HCN2_MA20_GoC.mod used in the Golgi-cell deposit of (Masoli et al., 2020) [3]. Two independent open-state gates, o_fast and o_slow, share one Boltzmann steady state split by a mixing fraction r(V) that is linear only inside a clamped voltage window:

\[\begin{split}\begin{aligned} I_h &= \phi_Q \, g_{\mathrm{max}} \, (o_{\mathrm{fast}} + o_{\mathrm{slow}}) \, (E - V) \\ o_\infty(V) &= \frac{1}{1 + \exp((V - E_{1/2}) \, c)} \\ r(V) &= \begin{cases} 0 & V \geq -64.70\ \mathrm{mV} \\ 1 & V \leq -108.70\ \mathrm{mV} \\ r_A V + r_B & \text{otherwise} \end{cases} \\ o_{\mathrm{fast},\infty} &= r(V) \, o_\infty(V) \\ o_{\mathrm{slow},\infty} &= (1 - r(V)) \, o_\infty(V) \\ \tau_{\mathrm{fast}} &= \exp((t_{Cf} V - t_{Df}) \, t_{Ef}) \\ \tau_{\mathrm{slow}} &= \exp((t_{Cs} V - t_{Ds}) \, t_{Es}) \end{aligned}\end{split}\]

with \(\phi_Q = Q_{10}^{(T - 23^{\circ}\mathrm{C}) / 10}\), \(E_{1/2} = -81.95\ \mathrm{mV}\), \(c = 0.1661\ \mathrm{mV^{-1}}\), \(r_A = -0.0227\ \mathrm{mV^{-1}}\), \(r_B = -1.4694\), \(t_{Cf} = 0.0269\ \mathrm{mV^{-1}}\), \(t_{Df} = -5.6111\), \(t_{Ef} = 2.3026\), \(t_{Cs} = 0.0152\ \mathrm{mV^{-1}}\), \(t_{Ds} = -5.2944\), \(t_{Es} = 2.3026\), and \(Q_{10} = 1.5\). Both gates additionally carry q10=3.0, temp_ref=23 degrees Celsius on their own state relaxation, independent of the \(\phi_Q\) conductance prefactor above. All eleven constants are fixed internal values set in __init__; they are not exposed as parameters.

This class subclasses HH directly, not OhmicHH, because current() sums two gate values before applying the driving force rather than taking a single power-weighted product.

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 0.08 mS/cm2.

  • E (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Reversal potential, default -20.0 mV.

  • temp (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Absolute temperature driving both the gate Q10 factors and \(\phi_Q\), default 22 degrees Celsius.

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

See also

HCN1_MA2020_GoC

Companion isoform with an unclamped r(V).

Notes

Ported from HCN2_MA20_GoC.mod. The former NEURON TABLE tabulated o_fast_inf, o_slow_inf, tau_f and tau_s over [-100, 30] mV and clamped outside that range; BrainCell evaluates the continuous formulas above at every call instead, so values outside [-100, 30] mV are expected to diverge from the original NEURON boundary-clamped output. The explicit r(V) clamp to {0, 1} above -64.70 mV / below -108.70 mV is reproduced directly in r(), independent of the removed TABLE boundary clamp.

HCN2_MA20_GoC.mod credits its kinetics data to “Santoro et al. J Neurosci. 2000” [2]; the Boltzmann/exponential functional forms trace to the cerebellar Golgi cell model of Solinas et al. (2007) [1].

References

current(V)[source]#

Calculate the current for this ion channel.

This method should be implemented by subclasses to compute the current based on the channel’s specific properties and state.

Parameters:

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

Raises:

NotImplementedError – This method must be implemented by subclasses.

root_type#

alias of HHTypedNeuron