Dendritic amplification of inhibitory postsynaptic potentials in a model Purkinje cell

Sergio M G Solinas, Reinoud Maex, Erik De Schutter

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

In neurons with large dendritic arbors, the postsynaptic potentials interact in a complex manner with active and passive membrane properties, causing not easily predictable transformations during the propagation from synapse to soma. Previous theoretical and experimental studies in both cerebellar Purkinje cells and neocortical pyramidal neurons have shown that voltage-dependent ion channels change the amplitude and time-course of postsynaptic potentials. We investigated the mechanisms involved in the propagation of inhibitory postsynaptic potentials (IPSPs) along active dendrites in a model of the Purkinje cell. The amplitude and time-course of IPSPs recorded at the soma were dependent on the synaptic distance from the soma, as predicted by passive cable theory. We show that the effect of distance on the amplitude and width of the IPSP was significantly reduced by the dendritic ion channels, whereas the rise time was not affected. Somatic IPSPs evoked by the activation of the most distal synapses were up to six times amplified owing to the presence of voltage-gated channels and the IPSP width became independent of the covered distance. A transient deactivation of the Ca(2+) channels and the Ca(2+)-dependent K(+) channels, triggered by the hyperpolarization following activation of the inhibitory synapse, was found to be responsible for these dynamics. Nevertheless, the position of activated synapses had a marked effect on the Purkinje cell firing pattern, making stellate cells and basket cells most suitable for controlling the firing rate and spike timing, respectively, of their target Purkinje cells.

Original languageEnglish
Pages (from-to)1207-18
Number of pages12
JournalEuropean Journal of Neuroscience
Volume23
Issue number5
DOIs
Publication statusPublished - Mar 2006

Keywords

  • Multi-compartmental neuron model
  • Calcium Channels
  • Dendrites
  • ACTIVE MEMBRANE MODEL
  • Membrane Potential
  • Models, Neurological
  • Potassium Channels, Calcium-Activated
  • Purkinje Cells
  • Cable equation
  • Synaptic Transmission
  • IPSP

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