Role of an A-type K+ conductance in the back-propagation of action potentials in the dendrites of hippocampal pyramidal neurons

Action potentials elicited in the axon actively back-propagate into the den dritic tree. During this process their amplitudes can be modulated by inter nal and external factors. We used a compartmental model of a hippocampal CA 1 pyramidal neuron to illustrate how this modulation could depend on (1) th e properties of an A-type K+ conductance that is expressed at high density in hippocampal dendrites and (2) the relative timing of synaptic activation . The simulations suggest that the time relationship between pre- and posts ynaptic activity could help regulate the amplitude of back-propagating acti on potentials, especially in the distal portion of the dendritic tree.