Schwaerzel Martin, Heisenberg Martin, Zars Troy
Theodor Boveri Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Biozentrum, Am Hubland, Würzburg, Germany.
Neuron. 2002 Aug 29;35(5):951-60. doi: 10.1016/s0896-6273(02)00832-2.
Memory loss occurs by diverse mechanisms, as different time constants of performance decrement and sensitivities to experimental manipulations suggest. While the phenomena of memory decay, interference, and extinction are well established behaviorally, little is known about them at the circuit or molecular level. In Drosophila, odorant memories lasting up to 3 hr can be localized to mushroom body Kenyon cells, a single neuronal level in the olfactory pathway. The plasticity underlying this memory trace can be induced without Kenyon cell synaptic output. Experimental extinction, i.e., presentation of the conditioned stimulus without the reinforcer, reduces memory performance and does so at the same circuit level as memory formation. Thus, unreinforced presentation of learned odorants antagonizes intracellularly the signaling cascade underlying memory formation.
记忆丧失通过多种机制发生，正如不同的行为表现衰退时间常数以及对实验操作的敏感性所表明的那样。虽然记忆衰退、干扰和消退现象在行为学上已得到充分证实，但在神经回路或分子水平上对它们的了解却很少。在果蝇中，持续长达3小时的嗅觉记忆可以定位到蘑菇体肯扬细胞，这是嗅觉通路中的单个神经元水平。这种记忆痕迹的可塑性可以在没有肯扬细胞突触输出的情况下被诱导。实验性消退，即呈现条件刺激而不给予强化物，会降低记忆表现，并且是在与记忆形成相同的神经回路水平上发生的。因此，未强化呈现已学习的气味剂会在细胞内拮抗记忆形成所依赖的信号级联反应。
