Temporal asymmetry in spike timing-dependent synaptic plasticity.

Activity-dependent synaptic modification is critical for the development and function of the nervous system. Recent experimental discoveries suggest that both the extent and the direction of modification may depend on the precise timing of pre- and postsynaptic action potentials (spikes). This phenomenon, termed spike timing-dependent plasticity (STDP), provides a new, quantitative interpretation of Hebb's rule and raises intriguing questions regarding the fundamental processes of cellular signaling. In this article, we summarize previous results obtained in a hippocampal culture system, where an asymmetric window of spike timing was found for paired pre- and postsynaptic spiking to induce STDP. We also discuss our recent studies using a "triplet-spiking" paradigm that reveals nonlinear, temporally asymmetric integration of STDP.