Either mGluR1 or mGluR5 is sufficient to facilitate prolonged rebound firing. A, Action potentials in a cerebellar nuclear cell, with a 500 ms, 100 Hz stimulus train, before and after application of JNJ16259685 (JNJ) and MPEP together. Fast excitatory input was blocked by DNQX and CPP. B, Summary of firing rate changes after stimulus trains before and after application of JNJ16259685 and MPEP together as in A or 3-MATIDA and MPEP together. ant., Antagonists. C, Same protocol in another cell, before and after application of JNJ16259685 alone. D, Summary of firing rate changes after stimulus trains as in C. E, Same protocol in another cell, before and after application of MPEP alone. F, Summary of firing rate changes after stimulus trains as in E. White symbols represent individual cells, and black symbols indicate mean ± SEM.