第1418回生物科学セミナー
Hierarchical architecture of dopaminergic circuits enables second-order conditioning in Drosophila
Dr. Yoshinori Aso（Group Leader, Janelia Research Campus）
2022年07月04日(月) 13:00-14:00 理学部2号館223号室及びZoom
Dopaminergic neurons with distinct projection patterns and physiological properties compose memory subsystems in a brain. However, it is poorly understood whether or how they interact during complex learning. Here, we identify a feedforward circuit formed between dopamine subsystems and show that it is essential for second-order conditioning, an ethologically important form of higher-order associative learning. The Drosophila mushroom body comprises a series of dopaminergic compartments, each of which exhibits distinct memory dynamics. We find that a slow and stable memory compartment can serve as an effective “teacher” by instructing other faster and transient memory compartments via a single key interneuron, which we identify by connectome analysis and neurotransmitter prediction. This excitatory interneuron acquires enhanced response to reward-predicting odor after first-order conditioning and, upon activation, evokes dopamine release in the “student” compartments. These hierarchical connections between dopamine subsystems explain distinct properties of first- and second-order memory long known by behavioral psychologists.
担当: 東京大学大学院理学系研究科・生物科学専攻・脳機能学研究室
