SYT1 and neurodevelopmental disorder: Given the controversy over SYT1 involvement in clamping and priming SVs, the observation of developmentally dependent effects of SYT2 in the calyx of Held (Kochubey et al., 2016), and the discovery of new point mutations in SYT1 gene associated with a neurodevelopmental disorder (Baker et al., 2018), we aimed to reanalyze the roles of Synaptotagmin-1 in SV priming, synchronized and spontaneous release as a function of neuronal culture age.