A role for synaptic inputs at distal dendrites: instructive signals for hippocampal long-term plasticity

Neuron. 2007 Dec 6;56(5):866-79. doi: 10.1016/j.neuron.2007.10.020.

Abstract

Synaptic potentials originating at distal dendritic locations are severely attenuated when they reach the soma and, thus, are poor at driving somatic spikes. Nonetheless, distal inputs convey essential information, suggesting that such inputs may be important for compartmentalized dendritic signaling. Here we report a new plasticity rule in which stimulation of distal perforant path inputs to hippocampal CA1 pyramidal neurons induces long-term potentiation at the CA1 proximal Schaffer collateral synapses when the two inputs are paired at a precise interval. This subthreshold form of heterosynaptic plasticity occurs in the absence of somatic spiking but requires activation of both NMDA receptors and IP(3) receptor-dependent release of Ca(2+) from internal stores. Our results suggest that direct sensory information arriving at distal CA1 synapses through the perforant path provide compartmentalized, instructive signals that assess the saliency of mnemonic information propagated through the hippocampal circuit to proximal synapses.

Publication types

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

MeSH terms

  • Absorptiometry, Photon
  • Animals
  • Calcium / metabolism
  • Computer Simulation
  • Dendrites / physiology*
  • Dendritic Spines / physiology
  • Electrophysiology
  • Excitatory Postsynaptic Potentials / physiology
  • Hippocampus / cytology
  • Hippocampus / physiology*
  • Inositol 1,4,5-Trisphosphate Receptors / physiology
  • Memory / physiology
  • Mice
  • Models, Neurological
  • Neuronal Plasticity / physiology*
  • Patch-Clamp Techniques
  • Pyramidal Cells / physiology
  • Receptors, AMPA / physiology
  • Receptors, N-Methyl-D-Aspartate / physiology
  • Recruitment, Neurophysiological / physiology
  • Signal Transduction / physiology*
  • Synapses / physiology*
  • Synaptic Transmission / physiology

Substances

  • Inositol 1,4,5-Trisphosphate Receptors
  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • Calcium