LTP promotes formation of multiple spine synapses between a single axon terminal and a dendrite

Nature. 1999 Nov 25;402(6760):421-5. doi: 10.1038/46574.

Abstract

Structural remodelling of synapses and formation of new synaptic contacts has been postulated as a possible mechanism underlying the late phase of long-term potentiation (LTP), a form of plasticity which is involved in learning and memory. Here we use electron microscopy to analyse the morphology of synapses activated by high-frequency stimulation and identified by accumulated calcium in dendritic spines. LTP induction resulted in a sequence of morphological changes consisting of a transient remodelling of the postsynaptic membrane followed by a marked increase in the proportion of axon terminals contacting two or more dendritic spines. Three-dimensional reconstruction revealed that these spines arose from the same dendrite. As pharmacological blockade of LTP prevented these morphological changes, we conclude that LTP is associated with the formation of new, mature and probably functional synapses contacting the same presynaptic terminal and thereby duplicating activated synapses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Axons / physiology*
  • Axons / ultrastructure
  • Calcium / metabolism
  • Dendrites / physiology*
  • Dendrites / ultrastructure
  • Hippocampus / physiology
  • Hippocampus / ultrastructure
  • Long-Term Potentiation / physiology*
  • Organ Culture Techniques
  • Synapses / physiology*
  • Synapses / ultrastructure
  • Time Factors

Substances

  • Calcium