Yagishita Sho
Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan; International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Neurosci Res. 2023 Mar;188:1-9. doi: 10.1016/j.neures.2022.12.003. Epub 2022 Dec 7.
Dopamine neurons exhibit transient increases and decreases in their firing rate upon reward and punishment for learning. This bidirectional modulation of dopamine dynamics occurs on the order of hundreds of milliseconds, and it is sensitively detected to reinforce the preceding sensorimotor events. These observations indicate that the mechanisms of dopamine detection at the projection sites are of remarkable precision, both in time and concentration. A major target of dopamine projection is the striatum, including the ventral region of the nucleus accumbens, which mainly comprises dopamine D1 and D2 receptor (D1R and D2R)-expressing spiny projection neurons. Although the involvement of D1R and D2R in dopamine-dependent learning has been suggested, the exact cellular bases for detecting transient dopamine signaling remain unclear. This review discusses recent cellular studies on the novel synaptic mechanisms for detecting dopamine transient signals associated with learning. Analyses of behavior based on these mechanisms have further revealed new behavioral aspects that are closely associated with these synaptic mechanisms. Thus, it is gradually possible to mechanistically explain behavioral learning via synaptic and cellular bases in rodents.
多巴胺神经元在学习的奖励和惩罚过程中，其放电频率会出现短暂的增加和减少。多巴胺动态的这种双向调节发生在数百毫秒的时间尺度上，并且能被灵敏地检测到，以强化先前的感觉运动事件。这些观察结果表明，多巴胺在投射部位的检测机制在时间和浓度上都具有显著的精确性。多巴胺投射的一个主要靶点是纹状体，包括伏隔核的腹侧区域，该区域主要由表达多巴胺D1和D2受体（D1R和D2R）的棘状投射神经元组成。尽管已经有人提出D1R和D2R参与了多巴胺依赖的学习过程，但检测短暂多巴胺信号的确切细胞基础仍不清楚。本综述讨论了近期关于检测与学习相关的多巴胺瞬态信号的新型突触机制的细胞研究。基于这些机制的行为分析进一步揭示了与这些突触机制密切相关的新行为方面。因此，逐渐有可能从啮齿动物的突触和细胞基础上对行为学习进行机制性解释。
