Gating of distal dendritic spikes by proximal inputs in hippocampal CA1 pyramidal cell neurons

This is an animation from a NEURON simulation of synaptic input in a CA1 pyramidal cell. First, distal input (indicated by the arrow) initiates dendritic spikes which fail to propagate to the main cell body (the soma). Next, more proximal Schaffer collateral input occurs; this generates dendritic spikes in the radial oblique side branches, but produces only subthreshold activity in the main apical dendrite. Finally, both inputs are activated simultaneously; in this case, the depolarization from the more proximal input "gates" the distal dendritic spikes, allowing them to propagate to the soma and produce a somatic action potential. For more details, see T. Jarsky, A. Roxin, W. L. Kath and N. Spruston, Conditional dendritic spike propagation following distal synaptic activation of hippocampal CA1 pyramidal neurons, Nature Neuroscience 8 (2005), pp. 1667-1676.