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 cryofixed samples (G) Average number of docked SV is equal (M18WT: 10.17 ± 0.38 SVs; M18Y473D: 10.75 ± 0.40 docked SVs, multilevel analysis, p = 0.264).(G-J) M18WT : N=3 independent cultures, n=159 synapses; M18Y473D: N=3 independent cultures, n=156 synapses. 