1. Neuromorphic synapse apparatus comprising: a memelement for storing a synaptic weight, the memelement being a phase-change memory cell adapted to exhibit a desired programming characteristic; and programming logic, responsive to a stimulus prompting update of the synaptic weight, for generating a programming signal for programming the memelement to update said weight, each said programming signal comprising a respective set of n programming pulses applied at an input electrode of said phase-change memory cell; wherein the programming logic is adapted to control at least one of the programming pulse shape and the value of n such that the programming signals exploit said programming characteristic to provide a desired weight-dependent synaptic update efficacy.