I simulate a neuron by compartments, where each compartment is represented by an electrical circuit. Myelinated nerves have reduced capacitance - so for example, if $n$ denotes the membrane layers, then the capacitance is C/n measured in [uF/cm^2]. Shouldn't random current fluctuations become smaller when capacitance is reduced? However, they do become larger - i.e. the random SCh fluctuations for a capacitance of
$C = 1 [uF/cm^2]$ are smaller than for $C = 1/5 [uF/cm^2]$ for example.
But does that make sense?
I model a neuron with a multi compartment model of the Hodgkin Huxley type - this means that the membrane voltage of each compartment can be determined with the HH equations. this figure shows the soma and with two adjacent compartments. If I reduce the capacitance of the soma, then (measured at the end of the axon) the fluctuations in the membrane voltage increase instead of decreasing.