Potential function of miRNAs in synaptic plasticity. Three different synapses for a single neuron are shown. Only the central one is active, as it receives an electrical pulse, and is potentiated. In the inactive synapses, translation of synaptic mRNAs (red and yellow) is prevented by miRNAs (miR) interacting with their 3'UTRs, an interaction supposedly stabilized by RNA binding proteins (RBP). A synaptic stimulus SS, represented by a neurotrophin or a neurotransmitter (e. g. BDNF and glutamate, respectively), is sensed by a receptor, in pink (e.g. TrkB or the NMDA receptor), and transmitted inside the neuron, in the vicinity of the active synapse. This signals triggers dissociation of the mRNA:miRNA:RBP complex, allowing the local translation of synaptic mRNAs. The neo-synthesized proteins (e. g. an AMPA receptor, in red, or some other synaptic component, in yellow) are utilized at the active synapse, contributing to strengthen its response.