Centre for Integrative Neuroscience, Hertie Institute for Clinical Brain Research, Department for Cognitive Neurology, University Tübingen, Tübingen, Germany.
Cerebellum. 2010 Mar;9(1):77-87. doi: 10.1007/s12311-009-0143-3.
How does the cerebellum participate in neocortical rhythms? Neocortical signals destined for the cerebellum are integrated in the pontine nuclei (PN) with cerebellar output signals via a direct, reciprocal feedback loop with the cerebellar nuclei (CN). The present study investigated the fate of two spontaneously occurring rhythms in rat neocortex under ketamine anesthesia-slow wave activity at around 1 Hz and gamma oscillations-within this pontonuclear feedback loop. Coordinated oscillatory neuronal activity was studied using simultaneous multineuron recordings in primary motor cortex (M1), PN, and lateral CN. It was revealed that slow burst firing-known in neocortex as "up and down states"-is readily conveyed within the pontonuclear feedback loop and thus engages the entire cerebropontocerebellothalamic loop. In contrast, gamma band synchronous oscillations reached only the PN under the present experimental conditions. Surprisingly, many CN single units were actually found to oscillate in the gamma range, but they completely failed to synchronize with other units in either CN or PN. These results show firstly that slow concerted activity can readily engage the entire cerebrocerebellar loop. Secondly, they raise the possibility that fast gamma oscillations may be incompatible with cerebellar processing and get blocked out. Future studies in behaving animals are needed to answer the question whether signals coded in gamma band frequency are converted to another carrier code using the feedback control exerted by the pontonuclear loop.
小脑如何参与新皮层节律？新皮层中 destined for 小脑的信号与小脑输出信号一起在桥核 (PN) 中整合，通过与小脑核 (CN) 的直接、互惠反馈环。本研究在氯胺酮麻醉下研究了大鼠新皮层中两种自发出现的节律的命运 - 约 1 Hz 的慢波活动和伽马振荡 - 在这个桥核反馈环内。使用在初级运动皮层 (M1)、PN 和外侧 CN 中的同时多神经元记录研究了协调的振荡神经元活动。结果表明，在桥核反馈环内，慢爆发发射 - 在新皮层中称为“上下状态” - 很容易传递，从而参与整个脑桥小脑丘脑环路。相比之下，在当前实验条件下，只有 PN 才能达到伽马波段同步振荡。令人惊讶的是，许多 CN 单个单元实际上被发现以伽马范围振荡，但它们完全不能与 CN 或 PN 中的其他单元同步。这些结果首先表明，缓慢的协调活动可以很容易地参与整个脑桥小脑环路。其次，它们提出了这样一种可能性，即快速伽马振荡可能与小脑处理不兼容，并被阻止。需要在行为动物中进行未来的研究，以回答以下问题：以伽马频带频率编码的信号是否使用桥核环施加的反馈控制转换为另一种载波代码。
