Abstract
Debate has raged over the past few years as to whether cortical neurons transmit information primarily in their average firing rates or in the precise timing of their spikes. Here, we address the related question of which features of spike trains control plasticity at cortical synapses. Using paired recording in slices we have developed a quantitative and predictive description of the joint dependence of cortical plasticity on the rate and relative timing of pre– and postsynaptic firing. The results hold important implications for which parts of the neural code are most readily stored for later retrieval.