title: Multiple forms of activity-dependent competition refine hippocampal circuits in vivo.
abstract: Efficient memory formation relies on the establishment of functional hippocampal circuits. It has been proposed that synaptic connections are refined by neural activity to form functional brain circuitry. However, it is not known whether and how hippocampal connections are refined by neural activity in vivo. Using a mouse genetic system in which restricted populations of neurons in the hippocampal circuit are inactivated, we show that inactive axons are eliminated after they develop through a competition with active axons. Remarkably, in the dentate gyrus, which undergoes neurogenesis throughout life, axon refinement is achieved by a competition between mature and young neurons. These results demonstrate that activity-dependent competition plays multiple roles in the establishment of functional memory circuits in vivo.
authors.affiliation: Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yasuda
authors.forename: Erin M
authors.initials: EM
authors.lastname: Johnson-Venkatesh
authors.forename: Helen
authors.initials: H
authors.lastname: Zhang
authors.forename: Jack M
authors.initials: JM
authors.lastname: Parent
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sutton
authors.forename: Hisashi
authors.initials: H
authors.lastname: Umemori
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology; D016922:Cellular Senescence / Q000502:physiology; D018891:Dentate Gyrus / Q000166:cytology / Q000502:physiology; D018728:Entorhinal Cortex / Q000166:cytology / Q000502:physiology; D020868:Gene Silencing; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology; D008568:Memory / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D055495:Neurogenesis / Q000502:physiology; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology / Q000502:physiology*