Developmental changes in the passive membrane properties of an identified molluscan neuron

We have studied developmentally the electrotonic fate of synaptic potentials in an identified giant neuron of the Pulmonate mollusc Achatina fulica. Our experimental preparation enabled us to sample spontaneously occurring excitatory postsynaptic potentials (EPSPs) from embryogenesis onward, while concomitantly analyzing the postsynaptic membrane properties. We observe non-monotonic changes in the electrotonic attenuation of synaptic inputs which invade the somata. Our data suggest that non-monotonic changes in the specific membrane resistance can account for these observations.