Computational roles of plastic probabilistic synapses

•Computational and experimental research suggest that synapses adapt their transmission statistics during learning.•Optimisation of probabilistic synapses occurs jointly in presynaptic and postsynaptic terminals during synaptic plasticity.•Recent developments in statistical learning point to a reevaluation of the function of probabilistic synapses in cortical circuits.•Insights on the biology of probabilistic synapses may inspire new learning algorithms.