SodiumFixed

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SodiumFixed#

class braincell.ion.SodiumFixed(size, E=Quantity(50., 'mV'), Ci=None, Co=None, valence=None, name=None, **channels)#

Fixed Sodium dynamics.

This sodium model has no dynamics. It holds a fixed reversal potential \(E\) and fixed concentrations \(C_i\)/\(C_o\).

Parameters:

  • size (int | Sequence[int] | integer | Sequence[integer]) – The size of the simulation target, typically the number of neurons or compartments. Forwarded unchanged to Sodium.

  • E (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable | None) – Fixed reversal potential. Defaults to +50 mV. Passing None explicitly raises ValueError; there is no class-default fallback for this argument.

  • Ci (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable | None) – Intracellular sodium concentration. Defaults to None, which falls back to Sodium.default_Ci inside FixedIon._init_fixed_ion().

  • Co (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable | None) – Extracellular sodium concentration. Defaults to None, which falls back to Sodium.default_Co inside FixedIon._init_fixed_ion().

  • valence (Array | ndarray | bool | number | bool | int | float | complex | Quantity | Callable | None) – Ionic valence. Defaults to None, which falls back to Sodium.default_valence inside FixedIon._init_fixed_ion().

  • name (str | None) – Runtime ion instance name. Defaults to None.

  • **channels – Channel instances to attach to this ion, forwarded unchanged to Sodium.

Raises:

ValueError – If E is explicitly passed as None. FixedIon._init_fixed_ion() requires an explicit fixed reversal potential and does not fall back to a class default for E.

See also

Sodium

Base sodium ion family this class fixes.

SodiumInitNernst

Sibling sodium model whose E is computed from the Nernst equation instead of fixed.

Notes

With the shipped class defaults (Co = 140.0 mM, Ci = 10.0 mM, valence = 1) at 36 degrees Celsius, the Nernst equation gives E = +70.31 mV. SodiumFixed instead defaults E to +50 mV, so the two sibling classes disagree by about 20 mV when both are constructed with no arguments.

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