Activity in neurons can strengthen or weaken signaling at a synapse.

1. High activity of neuron N₁ leads to recruitment of more axon terminals from the same neuron. Lack of activity at N₂ leads to loss of synapses.

2. If two synapses are often active at the same time, the strength of the postsynaptic response may increase at both synapses, mediated by long-term potentiation.