Keene Alex C, Krashes Michael J, Leung Benjamin, Bernard Jessica A, Waddell Scott
Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, USA.
Curr Biol. 2006 Aug 8;16(15):1524-30. doi: 10.1016/j.cub.2006.06.022.
Memories are formed, stabilized in a time-dependent manner, and stored in neural networks. In Drosophila, retrieval of punitive and rewarded odor memories depends on output from mushroom body (MB) neurons, consistent with the idea that both types of memory are represented there. Dorsal Paired Medial (DPM) neurons innervate the mushroom bodies, and DPM neuron output is required for the stability of punished odor memory. Here we show that stable reward-odor memory is also DPM neuron dependent. DPM neuron expression of amnesiac (amn) in amn mutant flies restores wild-type memory. In addition, disrupting DPM neurotransmission between training and testing abolishes reward-odor memory, just as it does with punished memory. We further examined DPM-MB connectivity by overexpressing a DScam variant that reduces DPM neuron projections to the MB alpha, beta, and gamma lobes. DPM neurons that primarily project to MB alpha' and beta' lobes are capable of stabilizing punitive- and reward-odor memory, implying that both forms of memory have similar circuit requirements. Therefore, our results suggest that the fly employs the local DPM-MB circuit to stabilize punitive- and reward-odor memories and that stable aspects of both forms of memory may reside in mushroom body alpha' and beta' lobe neurons.
记忆得以形成，以时间依赖的方式稳定下来，并存储于神经网络中。在果蝇中，惩罚性和奖励性气味记忆的提取依赖于蘑菇体（MB）神经元的输出，这与两种类型的记忆都在那里表征的观点一致。背侧配对内侧（DPM）神经元支配蘑菇体，且惩罚性气味记忆的稳定性需要DPM神经元的输出。在此我们表明，稳定的奖励性气味记忆也依赖于DPM神经元。在失忆（amn）突变果蝇中，DPM神经元中失忆基因（amn）的表达可恢复野生型记忆。此外，在训练和测试之间破坏DPM神经传递会消除奖励性气味记忆，就像对惩罚性记忆的作用一样。我们通过过表达一种DScam变体进一步研究了DPM与MB之间的连接，该变体可减少DPM神经元向MB的α、β和γ叶的投射。主要投射到MB的α'和β'叶的DPM神经元能够稳定惩罚性和奖励性气味记忆，这意味着两种形式的记忆具有相似的回路要求。因此，我们的结果表明，果蝇利用局部的DPM-MB回路来稳定惩罚性和奖励性气味记忆，且两种形式记忆的稳定方面可能存在于蘑菇体的α'和β'叶神经元中。
