Pathway Interactions and Synaptic Plasticity in the Dendritic Tuft Regions of CA1 Pyramidal Neurons

Neuron. 2009 Apr 16;62(1):102-11. doi: 10.1016/j.neuron.2009.03.007.

Abstract

Input comparison is thought to occur in many neuronal circuits, including the hippocampus, where functionally important interactions between the Schaffer collateral and perforant pathways have been hypothesized. We investigated this idea using multisite, whole-cell recordings and Ca2+ imaging and found that properly timed, repetitive stimulation of both pathways results in the generation of large plateau potentials in distal dendrites of CA1 pyramidal neurons. These dendritic plateau potentials produce widespread Ca2+ influx, large after-depolarizations, burst firing output, and long-term potentiation of perforant path synapses. Plateau duration is directly related to the strength and temporal overlap of pathway activation and involves back-propagating action potentials and both NMDA receptors and voltage-gated Ca2+ channels. Thus, the occurrence of highly correlated SC and PP input to CA1 is signaled by a dramatic change in output mode and an increase in input efficacy, all induced by a large plateau potential in the distal dendrites of CA1 pyramidal neurons.

MeSH terms

  • Anesthetics, Local / pharmacology
  • Animals
  • Animals, Newborn
  • Biophysics
  • Calcium / metabolism
  • Calcium Channel Blockers / pharmacology
  • Dendrites / physiology*
  • Electric Stimulation
  • Excitatory Amino Acid Antagonists / pharmacology
  • Hippocampus / cytology*
  • In Vitro Techniques
  • Inhibitory Postsynaptic Potentials / drug effects
  • Long-Term Potentiation / drug effects
  • Long-Term Potentiation / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Neural Pathways / cytology
  • Neural Pathways / physiology
  • Neuronal Plasticity / physiology*
  • Patch-Clamp Techniques / methods
  • Pyramidal Cells / cytology*
  • Pyramidal Cells / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Spider Venoms / pharmacology
  • Synapses / physiology*
  • Tetrodotoxin / pharmacology

Substances

  • Anesthetics, Local
  • Calcium Channel Blockers
  • Excitatory Amino Acid Antagonists
  • SNX 482
  • Spider Venoms
  • Tetrodotoxin
  • Calcium