We simulate the induction and maintenance of late long-term potentiation (L-LTP) in the hippocampal dentate gyrus by means of a new synaptic plasticity rule that is the result of combination of the spike-timing-dependent plasticity (STDP) and the moving LTD/LTP threshold yM from the Bienenstock, Cooper and Munro (BCM) theory of synaptic plasticity. We propose the activity-dependent functional equation for yM to be based on two processes: (1) fast process that depends on average postsynaptic spike count and (2) slow process that is a function of concentration of phosphorylated CREB (cAMP-responsive element binding) transcription factor, activation of which induces gene expression to maintain L-LTP. In the end, we propose a new, more general form of synaptic plasticity rule, which is applicable to any form of activity-dependent synaptic plasticity. r 2006 Elsevier B.V. All rights reserved.