Function Mapping of the Olfactory Tubercle-Ventral Pallidum Pathway in Positive and Negative Emotions

2023 Fiscal Year Final Research Report

• Project/Area Number: 17KK0190
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Nerve anatomy/Neuropathology
• Research Institution: University of Fukui
• Principal Investigator: Murata Koshi 福井大学, 学術研究院医学系部門, 助教 (10631913)
• Project Period (FY): 2018 – 2023
• Keywords: 嗅結節 / 腹側淡蒼球 / ドーパミン / オピオイド / 脳内報酬系 / 快情動 / 不快情動

Outline of Final Research Achievements

This study investigated whether the olfactory tubercle-ventral pallidum pathway is involved in the formation of positive and negative emotional responses. Behavioral pharmacology experiments were conducted by locally injecting the mu receptor agonist DAMGO, orexin peptide, and GABAA receptor agonist muscimol into the anteromedial or anterolateral domains of the rat olfactory tubercle, and the effects were evaluated using a taste reactivity test. In the anteromedial domain, the administration of each drug enhanced positive reactions (including drinking behavior). In contrast, no enhancement of positive reactions was observed with any drug when injected into the anterolateral domain. Additionally, this study introduced ultrasonic vocalizations as a new measure for assessing positive emotional responses in rats, finding that rats exhibited specific ultrasonic vocalizations when consuming chocolate, a highly preferred food.

Free Research Field

神経科学

Academic Significance and Societal Importance of the Research Achievements

本研究は嗅結節が快情動と不快情動の形成に関与することを明らかにし、嗅覚による情動形成の神経メカニズムの一端を解明した。また、ラットの超音波発声（USV）による快情動評価は簡便かつ有用であり、実験動物を用いた情動神経科学研究を加速させる新しい評価系を提案する。本研究の成果は嗅覚障害の治療や、食品の風味改善、摂食障害の治療法開発に寄与すると期待される。