Long-term rearrangements of hippocampal mossy fiber terminal connectivity in the adult regulated by experience

Neuron. 2006 Jun 1;50(5):749-63. doi: 10.1016/j.neuron.2006.04.026.


We investigated rearrangements of connectivity between hippocampal mossy fibers and CA3 pyramidal neurons. We found that mossy fibers establish 10-15 local terminal arborization complexes (LMT-Cs) in CA3, which exhibit major differences in size and divergence in adult mice. LMT-Cs exhibited two types of long-term rearrangements in connectivity in the adult: progressive expansion of LMT-C subsets along individual dendrites throughout life, and pronounced increases in LMT-C complexities in response to an enriched environment. In organotypic slice cultures, subsets of LMT-Cs also rearranged extensively and grew over weeks and months, altering the strength of preexisting connectivity, and establishing or dismantling connections with pyramidal neurons. Differences in LMT-C plasticity reflected properties of individual LMT-Cs, not mossy fibers. LMT-C maintenance and growth were regulated by spiking activity, mGluR2-sensitive transmitter release from LMTs, and PKC. Thus, subsets of terminal arborization complexes by mossy fibers rearrange their local connectivities in response to experience and age throughout life.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Dendrites / physiology
  • Housing, Animal
  • Long-Term Potentiation / physiology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Nerve Fibers / physiology*
  • Neural Pathways / physiology*
  • Neuronal Plasticity / physiology*
  • Organ Culture Techniques
  • Pyramidal Cells / cytology*