title: Long-term rearrangements of hippocampal mossy fiber terminal connectivity in the adult regulated by experience.
abstract: 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.
authors.affiliation: Friedrich Miescher Institut, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
authors.forename: Ivan
authors.initials: I
authors.lastname: Galimberti
authors.forename: Nadine
authors.initials: N
authors.lastname: Gogolla
authors.forename: Stefano
authors.initials: S
authors.lastname: Alberi
authors.forename: Alexandre Ferrao
authors.initials: AF
authors.lastname: Santos
authors.forename: Dominique
authors.initials: D
authors.lastname: Muller
authors.forename: Pico
authors.initials: P
authors.lastname: Caroni
mesh_terms: D000367:Age Factors; D000818:Animals; D003712:Dendrites / Q000502:physiology; D006799:Housing, Animal; D017774:Long-Term Potentiation / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009412:Nerve Fibers / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D009924:Organ Culture Techniques; D017966:Pyramidal Cells / Q000166:cytology*