Distinct dopamine neurons mediate reward signals for short- and long-term memories
Distinct dopamine neurons mediate reward signals for short- and long-term memories
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DOI：
10.1073/pnas.1421930112
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发表时间：
2014-12
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通讯作者：
Nobuhiro Yamagata;Toshiharu Ichinose;Yoshinori Aso;P. Plaçais;Anja B. Friedrich;Richard J Sima;T. Préat;G. Rubin;Hiromu Tanimoto
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作者：
Nobuhiro Yamagata;Toshiharu Ichinose;Yoshinori Aso;P. Plaçais;Anja B. Friedrich;Richard J Sima;T. Préat;G. Rubin;Hiromu Tanimoto
生物学相关事件，如在饥饿条件下寻找食物或中毒，可以在一次训练中驱动长期记忆（LTM）。这种强烈的奖励或惩罚诱导稳定记忆的神经元机制还知之甚少。在这里，我们表明，不同的多巴胺神经元的子集信号奖励的短期和长期的食欲的记忆在果蝇。由不同的奖励信号触发的记忆成分的时间动态是互补的，并且一起有助于暂时稳定的记忆保持。多巴胺神经元的两个子集可以发出不同的奖赏特性信号：甜味和糖的营养价值。因此，糖奖励在苍蝇大脑中被复杂地编码，因为与食物相关的长期记忆在生存中的重要性。当糖奖赏和气味配对呈现时，果蝇可以获得稳定的食欲嗅觉记忆。然而，一个单一的训练诱导长期记忆的神经机制知之甚少。在这里，我们表明，两个不同的子集的多巴胺神经元在苍蝇的大脑信号奖励短期（STM）和长期记忆（LTM）。一个子集诱导的记忆在几个小时内衰减，而另一个子集诱导的记忆在训练后逐渐发展。它们将奖励信号传递到蘑菇体（MB）的空间隔离突触域，这是一个潜在的收敛位点。此外，我们确定了一种单一类型的多巴胺神经元，该神经元将奖励信号传递到蘑菇体叶的受限子域并诱导长期记忆。因此，在一次训练后，持续的食欲记忆保持包括两个由不同的多巴胺神经元触发的记忆成分。
Significance A biologically relevant event such as finding food under starvation conditions or being poisoned can drive long-term memory (LTM) in a single training session. Neuronal mechanisms by which such a strong reward or punishment induces stable memory are poorly understood. Here we show that distinct subsets of dopamine neurons signal reward for short- and long-term appetitive memories in Drosophila. The temporal dynamics of memory components triggered by the distinct reward signals are complementary, and together contribute to a temporally stable memory retention. Two subsets of dopamine neurons could signal different reward properties: sweet taste and nutritional value of sugar. Sugar reward is thus intricately encoded in the fly brain, given the importance of long-lasting food-related memory in survival. Drosophila melanogaster can acquire a stable appetitive olfactory memory when the presentation of a sugar reward and an odor are paired. However, the neuronal mechanisms by which a single training induces long-term memory are poorly understood. Here we show that two distinct subsets of dopamine neurons in the fly brain signal reward for short-term (STM) and long-term memories (LTM). One subset induces memory that decays within several hours, whereas the other induces memory that gradually develops after training. They convey reward signals to spatially segregated synaptic domains of the mushroom body (MB), a potential site for convergence. Furthermore, we identified a single type of dopamine neuron that conveys the reward signal to restricted subdomains of the mushroom body lobes and induces long-term memory. Constant appetitive memory retention after a single training session thus comprises two memory components triggered by distinct dopamine neurons.