Fig. 2: Neurotransmission declines and motor behaviour is diminished during ageing.

a, b Representative traces of excitatory junctional currents (EJCs) (above) and miniature excitatory junctional currents (mEJCs) (below) from 5-day-old and 75-day-old A2 mvim  terminals. c Quantification of EJC amplitude decline during ageing. d Quantification of mEJC amplitude stability during ageing. e Quantification of mEJC frequency decline during ageing. f Quantification of declining motor ability during ageing. g Summary diagram indicates the progressive change of key ageing parameters as a percentage of the maximum observed phenotype. Compared to young animals (day 5) individual timepoints were significantly different at middle age (day 30) for increased bouton fragmentation, early old age (day 60) for EJC amplitude, early old age (day 60) for mEJC frequency and middle age (day 30) for motor ability. One-way ANOVA, **p = 0.004, R² = 0.31, n ≥ 7 presynaptic terminals per timepoint (c), *p = 0.04, R² = 0.11, n ≥ 13 presynaptic terminals per timepoint (d), **p = 0.004, R² = 0.15, n ≥ 13 presynaptic terminals per timepoint (e), ***p < 0.001, R² = 0.86, n ≥ 5 groups per timepoint (f), Tukey’s multiple comparison tests were used to compare the mean of each timepoint with the mean of all other timepoints (ns = not significant, *p ≤ 0.033, **p ≤ 0.002, ***p ≤ 0.001). All statistical analyses with a precise value of ‘n’ are reported in Supplementary Table 2 and in Source Data file. Data are represented as mean ± SD. n = biologically independent samples.