Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal.
Biology Department, Howard University, Washington, DC, USA.
Nat Neurosci. 2024 May;27(5):940-951. doi: 10.1038/s41593-024-01594-7. Epub 2024 Apr 2.
Supervised learning depends on instructive signals that shape the output of neural circuits to support learned changes in behavior. Climbing fiber (CF) inputs to the cerebellar cortex represent one of the strongest candidates in the vertebrate brain for conveying neural instructive signals. However, recent studies have shown that Purkinje cell stimulation can also drive cerebellar learning and the relative importance of these two neuron types in providing instructive signals for cerebellum-dependent behaviors remains unresolved. In the present study we used cell-type-specific perturbations of various cerebellar circuit elements to systematically evaluate their contributions to delay eyeblink conditioning in mice. Our findings reveal that, although optogenetic stimulation of either CFs or Purkinje cells can drive learning under some conditions, even subtle reductions in CF signaling completely block learning to natural stimuli. We conclude that CFs and corresponding Purkinje cell complex spike events provide essential instructive signals for associative cerebellar learning.
监督学习依赖于指导信号，这些信号塑造神经回路的输出，以支持行为的习得性改变。小脑皮层的 climbing fiber (CF) 输入代表了脊椎动物大脑中最强有力的候选者之一，用于传递神经指导信号。然而，最近的研究表明浦肯野细胞刺激也可以驱动小脑学习，这两种神经元类型在提供小脑依赖行为的指导信号方面的相对重要性仍未解决。在本研究中，我们使用特定于细胞类型的小脑回路元件的扰动，系统地评估它们对延迟眼跳条件反射的贡献。我们的研究结果表明，尽管光遗传学刺激 CF 或浦肯野细胞都可以在某些条件下驱动学习，但即使 CF 信号的细微减少也会完全阻止对自然刺激的学习。我们得出结论，CF 和相应的浦肯野细胞复合尖峰事件为联想性小脑学习提供了必要的指导信号。
