Slow integration leads to persistent action potential firing in distal axons of coupled interneurons

Nat Neurosci. 2011 Feb;14(2):200-7. doi: 10.1038/nn.2728. Epub 2010 Dec 8.


The conventional view of neurons is that synaptic inputs are integrated on a timescale of milliseconds to seconds in the dendrites, with action potential initiation occurring in the axon initial segment. We found a much slower form of integration that leads to action potential initiation in the distal axon, well beyond the initial segment. In a subset of rodent hippocampal and neocortical interneurons, hundreds of spikes, evoked over minutes, resulted in persistent firing that lasted for a similar duration. Although axonal action potential firing was required to trigger persistent firing, somatic depolarization was not. In paired recordings, persistent firing was not restricted to the stimulated neuron; it could also be produced in the unstimulated cell. Thus, these interneurons can slowly integrate spiking, share the output across a coupled network of axons and respond with persistent firing even in the absence of input to the soma or dendrites.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology*
  • Animals
  • Axons / physiology*
  • Cerebral Cortex / physiology
  • Dendrites / physiology
  • Hippocampus / physiology*
  • Interneurons / physiology*
  • Mice
  • Mice, Transgenic
  • Nerve Net / physiology
  • Patch-Clamp Techniques
  • Synapses / physiology