Implications of functional anatomy on information processing in the deep cerebellar nuclei.
Implications of functional anatomy on information processing in the deep cerebellar nuclei.
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DOI：
10.3389/neuro.03.014.2009
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发表时间：
2009-01-01
影响因子：
5.3
通讯作者：
Cohen, Dana
中科院分区：
文献类型：
--
作者：
Baumel, Yuval;Jacobson, Gilad A;Cohen, Dana
小脑被认为是产生颞敏锐度的主要参与者。小脑计时理论通常强调小脑皮层的作用，而忽略了提供小脑唯一输出的小脑深部核（DCN）的作用。在这里，我们回顾解剖和电生理研究，以阐明DCN支持小脑时间模式生成的能力。具体来说，我们检查了DCN结构的数据，DCN神经元的生物物理特性和传入系统的特性，以评估它们对DCN放电模式的贡献。此外，我们使用系统的毒碱注射来操作传入结构之一的下橄榄（IO），以测试对自由运动动物单个DCN神经元活动的网络效应。Harmaline在大约8赫兹的静止背景下诱导出有节奏的短脉冲放电模式。其他神经元则长时间（几秒到几分钟）处于静止状态。结果表明，正碱对DCN的作用主要是通过IO激活的抑制性浦肯野细胞（PCs）间接进行的，而不是通过直接的橄榄细胞激发。此外，我们认为DCN的响应特征主要取决于同时活动的pc的数量、它们的触发率以及它们在连续触发和静止之间转换时发生的同步水平。我们认为，DCN神经元忠实地传递由pc状态转换的强相关性产生的时间模式，而在很大程度上忽略了单个pc的简单峰值时间。未来的研究应着眼于量化PC状态转换对DCN活动的贡献，以及驱动DCN活动的不同传入系统之间的相互作用。
The cerebellum has been implicated as a major player in producing temporal acuity. Theories of cerebellar timing typically emphasize the role of the cerebellar cortex while overlooking the role of the deep cerebellar nuclei (DCN) that provide the sole output of the cerebellum. Here we review anatomical and electrophysiological studies to shed light on the DCN's ability to support temporal pattern generation in the cerebellum. Specifically, we examine data on the structure of the DCN, the biophysical properties of DCN neurons and properties of the afferent systems to evaluate their contribution to DCN firing patterns. In addition, we manipulate one of the afferent structures, the inferior olive (IO), using systemic harmaline injection to test for a network effect on activity of single DCN neurons in freely moving animals. Harmaline induces a rhythmic firing pattern of short bursts on a quiescent background at about 8 Hz. Other neurons become quiescent for long periods (seconds to minutes). The observed patterns indicate that the major effect harmaline exerts on the DCN is carried indirectly by the inhibitory Purkinje cells (PCs) activated by the IO, rather than by direct olivary excitation. Moreover, we suggest that the DCN response profile is determined primarily by the number of concurrently active PCs, their firing rate and the level of synchrony occurring in their transitions between continuous firing and quiescence. We argue that DCN neurons faithfully transfer temporal patterns resulting from strong correlations in PCs state transitions, while largely ignoring the timing of simple spikes from individual PCs. Future research should aim at quantifying the contribution of PC state transitions to DCN activity, and the interplay between the different afferent systems that drive DCN activity.