Conditions of Switching between Local Electric Activity Modes in the Dendritic Membrane of Hippocampal Pyramidal Neurons: A Simulation Study

摘要

On a computer model of an isolated dendrite segment populated by ion channels inherent in the hippocampus CA3 pyramidal neurons, the possibility and conditions of switching between different modes of intrinsic local activity induced by tonic synaptic excitation were investigated. Depending on the synaptic intensity, these were modes of generation of persistent low- or high-level depolarization or of steady oscillations of the membrane potential. The switches between the modes could be accomplished by application of depolarizing or hyperpolarizing currents of certain critical values. These currents from an extrinsic generator mimicked intrinsic axial core currents, which provide electrical coupling between the segments incorporated in a complex structure of the dendritic branching. Subcriticalintensity currents could change the persistent depolarization levels, frequency, and amplitude of steady oscillations of the membrane potential, but could not switch between the above-mentioned modes of activity.