title: TrkB signaling in parvalbumin-positive interneurons is critical for gamma-band network synchronization in hippocampus.
abstract: Although brain-derived neurotrophic factor (BDNF) is known to regulate circuit development and synaptic plasticity, its exact role in neuronal network activity remains elusive. Using mutant mice (TrkB-PV(-/-)) in which the gene for the BDNF receptor, tyrosine kinase B receptor (trkB), has been specifically deleted in parvalbumin-expressing, fast-spiking GABAergic (PV+) interneurons, we show that TrkB is structurally and functionally important for the integrity of the hippocampal network. The amplitude of glutamatergic inputs to PV+ interneurons and the frequency of GABAergic inputs to excitatory pyramidal cells were reduced in the TrkB-PV(-/-) mice. Functionally, rhythmic network activity in the gamma-frequency band (30-80 Hz) was significantly decreased in hippocampal area CA1. This decrease was caused by a desynchronization and overall reduction in frequency of action potentials generated in PV+ interneurons of TrkB-PV(-/-) mice. Our results show that the integration of PV+ interneurons into the hippocampal microcircuit is impaired in TrkB-PV(-/-) mice, resulting in decreased rhythmic network activity in the gamma-frequency band.
authors.affiliation: Gene, Cognition and Psychosis Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-3714, USA.
authors.forename: Kang
authors.initials: K
authors.lastname: Zheng
authors.forename: Juan Ji
authors.initials: JJ
authors.lastname: An
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.forename: Weifeng
authors.initials: W
authors.lastname: Xu
authors.forename: Zhi-Qing David
authors.initials: ZQ
authors.lastname: Xu
authors.forename: Jianyoung
authors.initials: J
authors.lastname: Wu
authors.forename: Tomas G M
authors.initials: TG
authors.lastname: Hökfelt
authors.forename: André
authors.initials: A
authors.lastname: Fisahn
authors.forename: Baoji
authors.initials: B
authors.lastname: Xu
authors.forename: Bai
authors.initials: B
authors.lastname: Lu
mesh_terms: D000200:Action Potentials; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000502:physiology; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D002452:Cell Count; D003712:Dendrites / Q000502:physiology; D059330:GABAergic Neurons / Q000502:physiology; D007395:Interneurons / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009415:Nerve Net / Q000166:cytology / Q000502:physiology; D010320:Parvalbumins / Q000378:metabolism; D020813:Receptor, trkB / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D010320:Parvalbumins; D020813:Receptor, trkB