  The cable equation is a second order, parabolic, partial differential
equation that describes the evolution of voltage in the dendrite of a neuron.
Here we look at the various ways in which lambda(space constant/ variable space
constant/length parameter) is calculated in the cases of linear, passive
transmission as well as nonlinear active transmission. Changes in morphology
are taken into account by including the case of tapering dendrite, branched
dendrites, branched dendrites with taper or flare. The case of variable
membrane resistance and the relationship between input resistance and space
constant is explored. Finally the reaction diffusion equation governing the
diffusion of calcium in dendrites and space constant associated with that is
described.
