Neurons expressing M18Y473D are not impaired at SV docking. Autaptic munc18-1 null hippocampal neurons expressing M18Y473D or M18WT as controls were analysed with electron microscopy on chemically fixed samples (B) Average number of docked SV (M18WT: 7.63 ± 0.15 SVs; M18Y473D: 8.45 ± 0.20 docked SVs, multilevel analysis, p = 0.047).(B-E) M18WT : N=6 autaptic neurons, n=137 synapses; M18Y473D: N=8 autaptic neurons, n=116 synapses. 