CaL_IS2008

class braincell.channel.CaL_IS2008(size, g_max=Quantity(1., 'mS / cm^2'), temp=Quantity(309.15, 'K'), q10_p=3.55, temp_ref_p=Quantity(297.15, 'K'), q10_q=3.0, temp_ref_q=Quantity(297.15, 'K'), V_sh=Quantity(0., 'mV'), name=None)

Inoue & Strowbridge 2008 L-type calcium current.

A voltage-gated calcium current with \(p^2 q\) HH gating and an ohmic driving force:

\[\begin{split}\begin{aligned} p_\infty &= \frac{1}{1 + \exp(-(V' + 10) / 4)} \\ \tau_p &= 0.4 + \frac{0.7} {\exp(-(V' + 5) / 15) + \exp((V' + 5) / 15)} \\ q_\infty &= \frac{1}{1 + \exp((V' + 25) / 2)} \\ \tau_q &= 300 + \frac{100} {\exp((V' + 40) / 9.5) + \exp(-(V' + 40) / 9.5)} \end{aligned}\end{split}\]

where \(V' = (V - V_{sh}) / \mathrm{mV}\), gating is \(p^2 q\), and \(\tau_p\)/\(\tau_q\) (in milliseconds) are further scaled by gate_phi().

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. Defaults to 1.0 mS/cm2.

• temp (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Absolute temperature driving the Q10 factors, default 36 degrees Celsius.

• q10_p (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Q10 scaling factor for the activation gate, default 3.55.

• temp_ref_p (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Reference temperature for q10_p, default 24 degrees Celsius.

• q10_q (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Q10 scaling factor for the inactivation gate, default 3.0.

• temp_ref_q (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Reference temperature for q10_q, default 24 degrees Celsius.

• V_sh (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable) – Threshold shift applied to both gates’ rates, default 0.0 mV.

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

See also

CaN_IS2008

Sibling channel from the same source paper, whose calcium-activated non-selective cation attribution is substantially, though not fully, supported (see its Notes).

Notes

Ported verbatim from BrainPy’s ICaL_IS2008 (brainpy/dyn/channels/calcium.py): every rate constant and the p^2 q gating scheme match exactly, and BrainPy attributes this current to Inoue & Strowbridge (2008) alone.

This attribution is contradicted by the cited paper’s own text. Inoue, T., & Strowbridge, B. W. (2008) models exactly two voltage-gated calcium currents in its olfactory bulb granule-cell simulations: “a low-threshold (T-type) Ca current, and a high-threshold (P/N-type) Ca current.” The strings “L-type”, “L type” and “ICaL” do not occur anywhere in the article text – the paper has no L-type calcium current for this class to be a port of. Two further, independent signs point the same way: this class’s q10_p = 3.55 / q10_q = 3.0 at 24 degrees Celsius defaults are byte-identical to CaT_HM1992’s temperature defaults (24 degC is the Huguenard & McCormick reference temperature, not an olfactory-bulb one), and no ModelDB deposit exists for this paper to compare constants against. The paper’s Methods also defer whatever gating constants it does report to supplementary materials not included with the PMC-deposited author manuscript, so even the P/N-type or T-type currents it does contain cannot be checked against this class from the text alone.

Because of this, either this class implements the paper’s high-threshold P/N-type current under the wrong name, or its true source is a different paper entirely; both possibilities remain open. This docstring ships no References section: printing a confident citation to Inoue & Strowbridge (2008) for an L-type current would misattribute a current that paper does not contain.

root_type

alias of Calcium