Cerebellar influences on saccade plasticity
Cerebellar influences on saccade plasticity
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DOI：
10.1111/j.1749-6632.2002.tb02816.x
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发表时间：
2002-01-01
期刊：
影响因子：
--
通讯作者：
Noto, CT
中科院分区：
文献类型：
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作者：
Robinson, FR;Fuchs, AF;Noto, CT
不准确的扫视适应变得更加准确。本实验研究了小脑对眼神经系统的输出在眼扫视大小适应中的作用。我们测量了眼跳适应后，暂时失活的眼跳相关神经元的尾侧部分的小脑顶核的项目眼脑干。用单单位记录法定位尾侧顶核神经元，并在其中注入0.1%蝇蕈醇。两只猴子接受双侧注射，两只猴子接受单侧注射。单侧注射使同向眼跳变大（增益>1.5），而逆向眼跳变小（增益接近0.6）。双侧注射均使眼动和眼动眼跳增大（增益>1.5）。在单侧失活过程中，同向或反向扫视的大小在1,000次扫视后都不适应。在双侧失活期间，适应性较小或非常缓慢。大多数完整的猴子在经历了1,000次左右的扫视后，完全适应了由扫视内目标位移引起的类似的辨距障碍。在接受双侧注射的猴子在每个水平方向上进行> 1，000次扫视后，我们将它们置于黑暗中，以便蝇蕈醇消散，而猴子没有收到关于其扫视增益的视觉反馈。在黑暗期之后，20度扫视被适应为小12%，4度扫视被适应为小7%。我们预计这种差异的适应，因为在尾顶核失活，猴子作出了许多大的过冲扫视和一些小的过冲扫视。我们从这些结果中得出结论：（1）尾侧小脑顶核的活动是重要的适应不等扫视;（2）双边尾侧小脑顶核失活损害中继适应信号的眼系统，但它并没有阻止所有的适应发生。
Inaccurate saccades adapt to become more accurate. In this experiment the role of cerebellar output to the oculomotor system in adapting saccade size was investigated. We measured saccade adaptation after temporary inactivation of saccade-related neurons in the caudal part of the fastigial nucleus which projects to the oculomotor brain stem. We located caudal fastigial nucleus neurons with single unit recording and injected 0.1% muscimol among them. Two monkeys received bilateral injections and two monkeys unilateral injections. Unilateral injections made ipsiversive saccades hypermetric (gains >1.5) and contraversive saccades hypometric (gains similar to0.6). Bilateral injections made both leftward and rightward saccades hypermetric (gains >1.5). During unilateral inactivation neither ipsiversive nor contraversive saccade size adapted after similar to1,000 saccades. During bilateral inactivation, adaptation was either small or very slow. Most intact monkeys completely adapt after similar to1,000 saccades to similar dysmetrias produced by intrasaccadic target displacement. After the monkeys receiving bilateral injections made >1,000 saccades In each horizontal direction, we placed them in the dark so that the muscimol dissipated without the monkeys receiving visual feedback about its saccade gain. After the dark period, 20-degree saccades were adapted to be 12% smaller, and 4-degree saccades to be 7% smaller. We expect this difference in adaptation because during caudal fastigial nucleus inactivation, monkeys made many large overshooting saccades and few small overshooting saccades. We conclude from these results that: (1) caudal fastigial nucleus activity is important in adapting dysmetric saccades; and (2) bilateral caudal fastigial nucleus inactivation impairs the relay of adapted signals to the oculomotor system, but it does not stop all adaptation from occurring.