Genes and Dynamics of Memory Systems, Neurobiology Unit, Centre National de Recherche Scientifique, École Supérieure de Physique et de Chimie Industrielles, Paris, France.
Nat Neurosci. 2012 Feb 26;15(4):592-9. doi: 10.1038/nn.3055.
A fundamental duty of any efficient memory system is to prevent long-lasting storage of poorly relevant information. However, little is known about dedicated mechanisms that appropriately trigger production of long-term memory (LTM). We examined the role of Drosophila dopaminergic neurons in the control of LTM formation and found that they act as a switch between two exclusive consolidation pathways leading to LTM or anesthesia-resistant memory (ARM). Blockade, after aversive olfactory conditioning, of three pairs of dopaminergic neurons projecting on mushroom bodies, the olfactory memory center, enhanced ARM, whereas their overactivation conversely impaired ARM. Notably, blockade of these neurons during the intertrial intervals of a spaced training precluded LTM formation. Two pairs of these dopaminergic neurons displayed sustained calcium oscillations in naive flies. Oscillations were weakened by ARM-inducing massed training and were enhanced during LTM formation. Our results indicate that oscillations of two pairs of dopaminergic neurons control ARM levels and gate LTM.
任何高效记忆系统的基本职责是防止长时间存储不相关的信息。然而，对于专门的机制来适当触发长期记忆（LTM）的产生，我们知之甚少。我们研究了果蝇多巴胺能神经元在控制 LTM 形成中的作用，发现它们在两条排他性的巩固途径之间充当开关，这两条途径分别导致 LTM 或麻醉抗性记忆（ARM）。在厌恶嗅觉条件作用后，阻断投射到蘑菇体（嗅觉记忆中心）的三对多巴胺能神经元，会增强 ARM，而过度激活这些神经元则会相反地损害 ARM。值得注意的是，在间隔训练的试验间隔期间阻断这些神经元会阻止 LTM 的形成。这两对多巴胺能神经元在未训练的果蝇中显示持续的钙振荡。ARM 诱导的密集训练削弱了振荡，而在 LTM 形成过程中则增强了振荡。我们的结果表明，两对多巴胺能神经元的振荡控制着 ARM 的水平，并控制着 LTM。
