Bistability of Dendrites

The theory of the ohmic electric function of dendrites is doubtful. A hypothesis was put forward that non-, partly or slow-accommodating neurons possess a slow inward dendritic current. It was predicted that these dendrites might be bistable, i.e., they might have stable depolarization in addition to the rest potential. Later, the prediction was confirmed experimentally: a steady inward current was observed when the motoneuron was clamped at the rest potential after strong depolarization. This current passes from dendrites to the soma because the distal dendritic membrane is under stable depolarization. The modeling of a neuron with bistable dendrites shows a hysteresis of the steady input current–voltage function and a hysteresis and jumps in the firing frequency–stimulating current relation. The theory of bistable dendrites explains a number of electrophysiological phenomena, and ascribes functional complexity to dendrites. Some experimental problems and neurocybernetical applications are suggested.