= Membrane time constant
{title2=$\tau_m=C/G$}
The <membrane time constant> of a passive uniform compartment is its <membrane capacitance> $C$ divided by its total fixed <electrical conductance> $G$. After input removal, voltage deviation from the relevant equilibrium undergoes <exponential decay>; in one <membrane time constant> it falls to $e^{-1}$ of its initial value. For leak alone, $G=g_L$; while fixed <synaptic conductances> are open, $G=g_L+\sum_jg_j$. Thus <shunting inhibition> can both reduce voltage responses and shorten the integration window. This is a local passive timescale: a branching <dendrite> can have several decay modes, and a time-varying <synaptic conductance> need not admit one constant $\tau_m$.
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