Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
Elife. 2021 Jun 1;10:e64907. doi: 10.7554/eLife.64907.
Regulation of reward signaling in the brain is critical for appropriate judgement of the environment and self. In , the protocerebral anterior medial (PAM) cluster dopamine neurons mediate reward signals. Here, we show that localized inhibitory input to the presynaptic terminals of the PAM neurons titrates olfactory reward memory and controls memory specificity. The inhibitory regulation was mediated by metabotropic gamma-aminobutyric acid (GABA) receptors clustered in presynaptic microdomain of the PAM boutons. Cell type-specific silencing the GABA receptors enhanced memory by augmenting internal reward signals. Strikingly, the disruption of GABA signaling reduced memory specificity to the rewarded odor by changing local odor representations in the presynaptic terminals of the PAM neurons. The inhibitory microcircuit of the dopamine neurons is thus crucial for both reward values and memory specificity. Maladaptive presynaptic regulation causes optimistic cognitive bias.
大脑中奖励信号的调节对于对环境和自我的适当判断至关重要。在这项研究中，原脑前内侧（PAM）簇多巴胺神经元介导奖励信号。在这里，我们表明，局部抑制输入到 PAM 神经元的突触前末梢可滴定嗅觉奖励记忆并控制记忆特异性。抑制调节是由聚集在 PAM 末梢突触前微域中的代谢型γ-氨基丁酸（GABA）受体介导的。通过增加内部奖励信号，细胞类型特异性沉默 GABA 受体可增强记忆。引人注目的是，GABA 信号的中断通过改变 PAM 神经元突触前末梢的局部气味表示来降低对奖励气味的记忆特异性。多巴胺神经元的抑制性微电路对于奖励值和记忆特异性都至关重要。突触前调节的适应性不良会导致乐观的认知偏差。
