(A) Scheme showing simultaneous recordings of cerebellar LFPs of lobules V and VI and tremor in a freely moving mouse. (B and C) Representative time-frequency plots and corresponding PSD diagrams in a WT mouse and a Grid2dupE3 mouse. (D) Group analysis of PSD peaks (n = 7 mice in each group, *P < 0.05 by Mann-Whitney tests). (E) Scheme demonstrating AAV-mediated ChR2 expression in the PCs, and an optic fiber was implanted in the DCN to activate PC axonal terminals. (F) AAV-CaMKIIa-eChR2-mCherry expression in lobules IV to VI. In the cerebellar cortex, CaMKIIa is a promoter specific for PCs. (G and H) Representative time-frequency plots and PSD diagrams of cerebellar oscillations, tremor, and coherence for optogenetic PC stimulation in a WT mouse. (I and J) Quantitative data of cerebellar LFP and tremor before, during, and after blue light stimulation (I) and also nonactivating green light control (J) (n = 4 mice in each group; **P < 0.01 by Wilcoxon signed-rank tests). Error bars denote SEM. CB, cerebellum. LFP, local field potential.