Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
Neurobiol Learn Mem. 2010 Mar;93(3):337-42. doi: 10.1016/j.nlm.2009.11.008. Epub 2009 Nov 27.
In most sensory modalities, neuronal inputs are bilaterally processed in a higher center. In some animal species, however, functional lateralization is sometimes observed in the sensory processing at the higher level. For the terrestrial slug Limax, olfaction is the most important sensory modality and this slug can acquire odor-aversion memories. Previously, it has been demonstrated in bilateral PC ablation experiments that the procerebrum (PC) is necessary for odor-aversion memory, and that the PC is the memory storage site. On the other hand, it has been hypothesized that only the unilateral PC is used for odor-aversion learning. Here we demonstrated that the number of the slugs with intact memory performance was reduced by approximately 50% when the PC was surgically ablated only unilaterally before or after conditioning. There was no difference in the memory performance of the right vs. the left PC-ablated slugs. However, memory deficit from unilateral PC ablation was not observed when the ipsilateral tentacles were also amputated at the same time. We also showed that there was no lateral memory transfer from one PC to the other, after up to 7 days post-conditioning. Our results demonstrated clearly that either the left or right PC is randomly used for olfactory learning, and that the side of use is determined at the level of the olfactory ascending pathway to the PC.
在大多数感觉模态中，神经元输入在高级中枢双侧处理。然而，在某些动物物种中，在高级水平的感觉处理中有时会观察到功能偏侧化。对于陆生蜗牛 Limax，嗅觉是最重要的感觉模态，并且这种蜗牛可以获得厌恶记忆。以前，在双侧 PC 消融实验中已经证明，前脑（PC）是厌恶记忆所必需的，并且 PC 是记忆存储部位。另一方面，有人假设只有单侧 PC 用于厌恶学习。在这里，我们证明了当 PC 在条件作用之前或之后仅单侧手术消融时，具有完整记忆性能的蜗牛数量减少了约 50%。右 PC 消融的蜗牛和左 PC 消融的蜗牛的记忆性能没有差异。然而，当同时切除同侧触须时，单侧 PC 消融不会引起记忆缺陷。我们还表明，在条件作用后长达 7 天，从一个 PC 到另一个 PC 没有侧记忆转移。我们的结果清楚地表明，要么是左 PC 要么是右 PC 随机用于嗅觉学习，并且使用的侧是在通向 PC 的嗅觉上行途径的水平上确定的。
