Calcium plays a critical role in several synaptic transduction pathways. We report and discuss here fast calcium transients and how they are possible in dendritic spines. The talk will discuss fast calcium transients and how there are generated. We showed that the fastest particles to arrive to receptors lead to an  molecular amplification. The associated theory falls into narrow escape extreme statistics, that revealed the asymmetric organization of receptors located on the endoplasmic reticulum. In that context, we will discuss the role of redundancy. To conclude, the local nanometer molecular organization defines kinetics and efficacy of transduction, such as calcium transients in neuronal physiology.