The effects of feedback from the auditory cortex to the inferior colliculus on vocalization cognition

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K21238
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0909:Sports sciences, physical education, health sciences, and related fields
• Research Institution: University of Toyama
• Principal Investigator: Takahashi Katsumasa 富山大学, 学術研究部医学系, 特命助教 (40965795)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: マウス / 聴覚野 / 下丘 / 超音波発声

Outline of Final Research Achievements

To investigate in detail the neurons projecting from the auditory cortex (AC) to the inferior colliculus (IC), tracer experiments using adeno-associated virus and immunohistochemical staining were performed on mice. The results showed that layers 5 and 6 showed strong responses in the AC. In the IC, regions other than the central nucleus showed strong responses. Positive cells were also observed in the peripeduncular nucleus, part of the thalamus, and in the intermediate nucleus of the lateral lemniscus, part of the auditory pathway, as brain regions intermediate between the AC and the IC.
We observed the behavior of mice in response to ultrasonic vocalizations (USVs). When presented with the USV of the individual being chased during the resident-intruder test, they recognized it and took an approach behavior toward the sound source.

Free Research Field

行動神経科学

Academic Significance and Societal Importance of the Research Achievements

これまで音声認知の神経メカニズムは，末梢において単純な音に反応する広範囲に分散した神経活動を，上行性聴覚伝導路が徐々に不均一化・複雑化させるといった処理で意味を符号化していると考えられてきたが，下行性投射が音声認知に与える影響については不明であった。本研究は，聴覚野から下丘への投射を調査することで，聴覚神経回路のトップダウン制御がコミュニケーション音声認知に与える影響を行動学と電気生理学の両面から検証する最初の研究であり，本成果は聴覚情報処理障害の診断や治療・予防・（リ）ハビリテーションに関する多くの研究領域に，エビデンスに基づく新たな手がかりを提供できる。