A system of feed-forward cerebellar circuits that extend and diversify sensory signaling.
A system of feed-forward cerebellar circuits that extend and diversify sensory signaling.
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一种前馈小脑回路系统，可扩展感觉信号并使之多样化。
DOI：
10.1101/2023.04.11.536335
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Balmer,TimothyS
中科院分区：
文献类型：
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作者：
Hariani,HarshN;Algstam,ABrynn;Candler,ChristianT;Witteveen,IsabelleF;Sidhu,JasmeenK;Balmer,TimothyS
感觉信号由小脑处理，以协调运动。许多小脑功能被认为需要维持超出输入信号的感觉表征。颗粒细胞接受感觉输入，但它们不会延长信号，因此不太可能比输入本身保持感觉表征的时间更长。单极刷状细胞是一种兴奋性中间神经元，它投射到颗粒细胞，并将感觉输入转换为长时间的放电增加或减少，这取决于其UBC亚型的开启或关闭。输入信号的进一步扩展和多样化可以由相互投射的UBC产生，但这种电路是否存在尚不清楚。在这里，我们测试UBC是否相互支配，并探索这些UBC的小网络如何改变尖峰模式。我们对两个转基因小鼠系进行了电生理学和免疫组织化学鉴定，以确认它们标记了ON和OFF UBC亚型，并将它们杂交在一起，揭示了ON和OFF UBC相互作用。用不同的荧光蛋白标记同一ON或OFF亚型的UBC，结果表明UBC也分布在各自的亚型中。计算模型预测，这些UBC的前馈网络延长了突发或暂停的长度，并引入了延迟-从眼球运动到跨时间尺度的自适应学习的小脑功能可能需要的转换。
Sensory signals are processed by the cerebellum to coordinate movements. Numerous cerebellar functions are thought to require the maintenance of a sensory representation that extends beyond the input signal. Granule cells receive sensory input, but they do not prolong the signal and are thus unlikely to maintain a sensory representation for much longer than the inputs themselves. Unipolar brush cells (UBCs) are excitatory interneurons that project to granule cells and transform sensory input into prolonged increases or decreases in firing, depending on their ON or OFF UBC subtype. Further extension and diversification of the input signal could be produced by UBCs that project to one another, but whether this circuitry exists is unclear. Here we test whether UBCs innervate one another and explore how these small networks of UBCs could transform spiking patterns. We characterized two transgenic mouse lines electrophysiologically and immunohistochemically to confirm that they label ON and OFF UBC subtypes and crossed them together, revealing that ON and OFF UBCs innervate one another. A Brainbow reporter was used to label UBCs of the same ON or OFF subtype with different fluorescent proteins, which showed that UBCs innervate their own subtypes as well. Computational models predict that these feed-forward networks of UBCs extend the length of bursts or pauses and introduce delays—transformations that may be necessary for cerebellar functions from modulation of eye movements to adaptive learning across time scales.