Relating Cerebellar Purkinje Cell Activity to the Timing and Amplitude of Conditioned Eyelid Responses
Relating Cerebellar Purkinje Cell Activity to the Timing and Amplitude of Conditioned Eyelid Responses
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DOI：
10.1523/jneurosci.3663-14.2015
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发表时间：
2015-05-20
影响因子：
5.3
通讯作者：
Mauk, Michael D.
中科院分区：
文献类型：
--
作者：
Halverson, Hunter E.;Khilkevich, Andrei;Mauk, Michael D.
学习如何改变浦肯野细胞（PC）的活动是小脑理论的核心。巴甫洛夫眼睑条件反射，因为它直接作用于小脑，帮助揭示了小脑学习的许多方面和潜在机制。小脑学习理论认为，攀爬纤维的输入控制着pc突触的可塑性，因此pc控制学习反应的表达。我们通过记录训练良好的家兔在条件眼睑反应（CRs）表达过程中的184个眼睑pc和240个非眼睑pc来验证这一论断。通过对比眼睑和非眼睑pc的反应，以及对比眼睑pc在产生不同时间cr的条件下的反应，我们验证了眼睑pc的学习相关变化有助于cr的学习和适应时间的假设。我们使用各种分析来测试眼睑PC响应与眼睑cr运动特性之间的定量关系。我们发现，眼睑PC反应的时间随行为cr的时间而系统性地变化，并且在大cr、小cr和非cr试验中，眼睑PC反应的幅度存在差异。然而，眼睑PC活动不编码固定时滞下行为CR的任何单一运动特性，也不线性编码CR幅度。即便如此，研究结果还是与之前的假设相一致，即学习依赖性的PC活动变化有助于条件眼睑反应的适应性定时表达。
How Purkinje cell (PC) activity may be altered by learning is central to theories of the cerebellum. Pavlovian eyelid conditioning, because of how directly it engages the cerebellum, has helped reveal many aspects of cerebellar learning and the underlying mechanisms. Theories of cerebellar learning assert that climbing fiber inputs control plasticity at synapses onto PCs, and thus PCs control the expression of learned responses. We tested this assertion by recording 184 eyelid PCs and 240 non-eyelid PCs during the expression of conditioned eyelid responses (CRs) in well trained rabbits. By contrasting the responses of eyelid and non-eyelid PCs and by contrasting the responses of eyelid PCs under conditions that produce differently timed CRs, we test the hypothesis that learning-related changes in eyelid PCs contribute to the learning and adaptive timing of the CRs. We used a variety of analyses to test the quantitative relationships between eyelid PC responses and the kinematic properties of the eyelid CRs. We find that the timing of eyelid PC responses varies systematically with the timing of the behavioral CRs and that there are differences in the magnitude of eyelid PC responses between larger-CR, smaller-CR, and non-CR trials. However, eyelid PC activity does not encode any single kinematic property of the behavioral CRs at a fixed time lag, nor does it linearly encode CR amplitude. Even so, the results are consistent with the hypothesis that learning-dependent changes in PC activity contribute to the adaptively timed expression of conditioned eyelid responses.