Active forgetting is an essential component of the memory management system of the brain¹. Forgetting can be permanent, in which prior memory is lost completely, or transient, in which memory exists in a temporary state of impaired retrieval. Temporary blocks on memory seem to be universal, and can disrupt an individual’s plans, social interactions and ability to make rapid, flexible and appropriate choices. However, the neurobiological mechanisms that cause transient forgetting are unknown. Here we identify a single dopamine neuron in Drosophila that mediates the memory suppression that results in transient forgetting. Artificially activating this neuron did not abolish the expression of long-term memory. Instead, it briefly suppressed memory retrieval, with the memory becoming accessible again over time. The dopamine neuron modulates memory retrieval by stimulating a unique dopamine receptor that is expressed in a restricted physical compartment of the axons of mushroom body neurons. This mechanism for transient forgetting is triggered by the presentation of interfering stimuli immediately before retrieval.

主动遗忘是大脑¹记忆管理系统的重要组成部分。遗忘可以是永久性的，其中先前的记忆完全丢失，也可以是短暂的，其中记忆存在于检索受损的临时状态。记忆似乎是普遍的，可以扰乱个人的计划，社会互动和能力，使快速，灵活和适当的选择。然而，导致短暂遗忘的神经生物学机制尚不清楚。在这里，我们确定了果蝇中的单个多巴胺神经元介导导致短暂遗忘的记忆抑制。人工激活这个神经元并没有消除长期记忆的表达。相反，它短暂地抑制了记忆检索，随着时间的推移记忆再次变得可访问。多巴胺神经元通过刺激一种独特的多巴胺受体来调节记忆恢复，该受体在蘑菇体神经元轴突的受限物理隔室中表达。这种短暂遗忘的机制是由在检索之前立即出现干扰刺激而触发的。