Selective reduction of weak synaptic activity awakens dormant synapses.

Slutsky et al. (this issue of Neuron) report that by selectively filtering out low-level uncorrelated synaptic activity at NMDA receptors in hippocampal cultures they can unlock a large reserve of quiescent synapses and make them available for potentiation with theta burst stimulation. These findings differ from previously reported activity-dependent mechanisms in that inactivity does not necessarily increase synaptic activity globally.