title: Synaptic plasticity associated with a memory engram in the basolateral amygdala.
abstract: Synaptic plasticity is a cellular mechanism putatively underlying learning and memory. However, it is unclear whether learning induces synaptic modification globally or only in a subset of neurons in associated brain regions. In this study, we genetically identified neurons activated during contextual fear learning and separately recorded synaptic efficacy from recruited and nonrecruited neurons in the mouse basolateral amygdala (BLA). We found that the fear learning induces presynaptic potentiation, which was reflected by an increase in the miniature EPSC frequency and by a decrease in the paired-pulse ratio. Changes occurred only in the cortical synapses targeting the BLA neurons that were recruited into the fear memory trace. Furthermore, we found that fear learning reorganizes the neuronal ensemble responsive to the conditioning context in conjunction with the synaptic plasticity. In particular, the neuronal activity during learning was associated with the neuronal recruitment into the context-responsive ensemble. These findings suggest that synaptic plasticity in a subset of BLA neurons contributes to fear memory expression through ensemble reorganization.
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Nonaka
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Toyoda
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miura
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Hitora-Imamura
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Naka
authors.affiliation: Division of Morphological Neuroscience, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Eguchi
authors.affiliation: Division of Morphological Neuroscience, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan, PRESTO, Japan Science and Technology Agency (JST), Saitama 332-0012, Japan, and.
authors.forename: Shun
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan, Center for Information and Neural Networks, Suita City, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikegaya
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Matsuki
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan, nomura@mol.f.u-tokyo.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nomura
mesh_terms: D000679:Amygdala / Q000502:physiology*; D000818:Animals; D003216:Conditioning, Operant / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D017774:Long-Term Potentiation / Q000502:physiology; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*