title: Elevated expression of brain-derived neurotrophic factor facilitates visual imprinting in chicks.
abstract: With the aim of elucidating the neural mechanisms of early learning, we studied the role of brain-derived neurotrophic factor (BDNF) in visual imprinting in birds. The telencephalic neural circuit connecting the visual Wulst and intermediate medial mesopallium is critical for imprinting, and the core region of the hyperpallium densocellulare (HDCo), situated at the center of this circuit, has a key role in regulating the activity of the circuit. We found that the number of BDNF mRNA-positive cells in the HDCo was elevated during the critical period, particularly at its onset, on the day of hatching (P0). After imprinting training on P1, BDNF mRNA-positive cells in the HDCo increased in number, and tyrosine phosphorylation of TrkB was observed. BDNF infusion into the HDCo at P1 induced imprinting, even with a weak training protocol that does not normally induce imprinting. In contrast, K252a, an antagonist of Trk, inhibited imprinting. Injection of BDNF at P7, after the critical period, did not elicit imprinting. These results suggest that BDNF promotes the induction of imprinting through TrkB exclusively during the critical period.
authors.affiliation: Division of Biology, College of Liberal Arts and Sciences, Kitasato University, Sagamihara, Kanagawa, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Suzuki
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Maekawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Nakamori
authors.forename: Hayato
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kanamatsu
authors.forename: Kohichi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ohki-Hamazaki
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis*; D002645:Chickens; D003423:Critical Period, Psychological; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D007173:Imprinting, Psychological / Q000502:physiology*; D017403:In Situ Hybridization; D012333:RNA, Messenger / Q000032:analysis; D020813:Receptor, trkB / Q000378:metabolism*; D014162:Transfection; D014795:Visual Pathways / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D020813:Receptor, trkB