Synaptic plasticity, which underlies learning and memory, involves the strengthening and weakening of synapses. This process is affected by the relative timing of spikes in electrical activity in the pre- and postsynaptic neurons. Researchers have now found that, when both spikes occur simultaneously (or within tens of milliseconds of each other), the synapses were strengthened for up to 4 hours. These findings could impact research in conditions with impaired learning and memory.