Fig. 3

Fmr1 KO synapses have increased RRP size and lack cerebellar PF-PC LTP. a Changes in the PPR (mean of 6 consecutive pairs of stimuli delivered at 0.05 Hz) compared to WT at different inter-interval stimuli (ISI) (WT: n = 8 cells, 8 slices, 3 mice. Fmr1 KO: n = 9 cells, 9 slices, 3 mice. Scale bars: 100 pA, 20 ms), b changes in synaptic efficacy (mean of 6 consecutive EPSCs delivered at 0.05 Hz) compared to WT at different stimuli intensity (WT: n = 6 cells, 6 slices, 3 mice. Fmr1KO: n = 7 cells, 7 slices, 3 mice). Scale bars: 500 pA, 1 ms. c Changes in EPSC amplitude induced by a 10 Hz stimulation. d Quantification of EPSCs (mean of 6 consecutive EPSCs delivered at 0.05 Hz) 30 min after stimulation (2) compared to the respective values before stimulation (1): WT, (n = 9 cells/9 slices/5 mice); WT/propranolol (100 μM, 30 min, n = 10 cells/10 slices/6 mice); Fmr1 KO (n = 12 cells/12 slices/9 mice). Scale bars: 50 pA, 10 ms. e Changes in the PPR. f Quantification of the changes in PPR (mean of 6 consecutive pairs of stimuli delivered at 0.05 Hz) compared to the respective values before stimulation: WT (n = 9 cells/9 slices/5 mice); WT/propranolol (100 μM, 30 min, n = 10 cells/10 slices/6 mice); Fmr1 KO (n = 12 cells/12 slices/9 mice). Scale bars: 20pA, 10 ms. g, i Cumulative EPSC amplitudes in WT and Fmr1KO slices before (basal) and 30 min after LTP induction by 10 Hz stimulation (10 Hz). RRP size was calculated from the cumulative amplitude plots as the y-intercept from a linear fit of the steady-state level attained during a train of 100 stimuli at 40 Hz (as see in c). h, j Quantification of the RRP size: WT (n = 11 cells/11 slices/5 mice: **P < 0.01); Fmr1KO (n = 13 cells/13 slices/6 mice: P > 0.05, comparing 10 Hz vs basal values). RRP size WT basal vs Fmr1KO basal (^#P < 0.05). Bar graphs show raw data and the mean. *P < 0.05, **P < 0.01, ***P < 0.001, ^#P < 0.05, unpaired Student’s t test or Welch test when the variances of the populations were significantly different