An undisturbed Physarum exhibits more or less regular patterns
of oscillation of its surface electrical potential. The electrical
potential oscillations are likely controlling the peristaltic activity
of protoplasmic tubes, necessary for the distribution of nutrients
in the spatially extended body of Physarum . A calcium ion
flux through the membrane triggers oscillations responsible for
the dynamics of contractile activity . The Physarum surface
electrical potential oscillates with an amplitude of 1–10 mV and a
period of 50–200 s, associated with shuttle streaming of cytoplasm
[29–32]. Oscillations of the electrical potential and the corresponding
peristaltic activity are due to calcium waves propagating
along protoplasmic tubes. These waves, and the associated electrical
charges, plus the difference in electrical potential leads to a
flow of cytoplasm.