Encoding of syllable sequence by context dependent response modulation in auditory neurons

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K07067
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology / General neuroscience
• Research Institution: Okinawa Institute of Science and Technology Graduate University
• Principal Investigator: Araki Makoto 沖縄科学技術大学院大学, 臨界期の神経メカニズム研究ユニット, 研究員 (60649078)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 形態学的細胞同定 / 脳透明化手法 / 光シート蛍光顕微鏡

Outline of Final Research Achievements

Juvenile zebra finches learn song syllables and those sequence from adult conspecifics, but how the syllable sequence is encoded in neural activity is not yet understood. Output layer of primary auditory area (L3) has longer temporal integration period than input layer and has small number of neurons sensitive to order of syllables makes it good candidate area for the sequence encoding. I focused on LF and HF neurons which encode syllable sound morphology and song tempo, respectively, and hypothesized that the sequence information is co-expressed in their neural activity. These neurons have yet identified morphologically, therefore, I constructed morphological models of LF and HF neurons by loading tracer directly to the cells after confirming their characteristic auditory responses. Morphological character of LF and HF neurons were compared to morphological models obtained from population of L3 neurons expressed fluorescent proteins to clarify their morphological identity.

Free Research Field

電気生理学

Academic Significance and Societal Importance of the Research Achievements

神経細胞間のシナプスを介した情報伝達や神経細胞内での情報の統合・発火活動は細胞の形態と強く結びついている。本研究では、活動記録によって神経機能の同定を行った細胞の形態的特徴を大規模な神経形態学的な分類群と比較することでその特異な点を明らかにする、という古典的な形態同定手法を脳サンプルを透明化し大規模光学切片を得ることで大規模化・効率化した点で特色がある。同手法を用いて機能同定された細胞種間の空間的配置を明らかにすることで、明確な細胞層構造を持たないような脳領域において局所神経回路の推定に寄与することが期待される。