Background synaptic conductance and precision of EPSP-spike coupling at pyramidal cells

J Neurophysiol. 2005 Jun;93(6):3248-56. doi: 10.1152/jn.01027.2004. Epub 2005 Feb 16.


The temporal precision of converting excitatory postsynaptic potentials (EPSPs) into spikes at pyramidal cells is critical for the coding of information in the cortex. Several in vitro studies have shown that voltage-dependent conductances in pyramidal cells can prolong the EPSP time course resulting in an imprecise EPSP-spike coupling. We have used dynamic-clamp techniques to mimic the in vivo background synaptic conductance in cortical slices and investigated how the ongoing synaptic activity may affect the EPSP time course near threshold and the EPSP spike coupling. We report here that background synaptic conductance dramatically diminished the depolarization related prolongation of the EPSPs in pyramidal cells and improved the precision of spike timing. Furthermore, we found that background synaptic conductance can affect the interaction among action potentials in a spike train. Thus the level of ongoing synaptic activity in the cortex may regulate the capacity of pyramidal cells to process temporal information.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cerebral Cortex / cytology*
  • Electric Stimulation / methods
  • Excitatory Postsynaptic Potentials / physiology*
  • Excitatory Postsynaptic Potentials / radiation effects
  • In Vitro Techniques
  • Neural Conduction / physiology
  • Neural Conduction / radiation effects
  • Neural Inhibition / physiology
  • Patch-Clamp Techniques / methods
  • Pyramidal Cells / physiology*
  • Pyramidal Cells / radiation effects
  • Rats
  • Reaction Time / physiology
  • Reaction Time / radiation effects
  • Synapses / physiology*
  • Synaptic Transmission / physiology*
  • Time Factors