Metaplasticity has been theoretically linked to the Bienenstock-Cooper-Munro (BCM) rule. In this process, however, a mechanism for the activity-dependent regulation of the modification threshold (θ) has remained an open question. In this simulation study of CA1 pyramidal cells, we used a modification of the calcium dependent hypothesis proposed by (Shouval et al, PNAS, 99(16), 2002) and show that the hyperpolarization-activated cation current Ih is capable of shifting θ by regulating intracellular calcium levels. Specifically, our results suggest that an up/downregulation of Ih leads to an increase/decrease in θ. Taken along with recent results that LTP/LTD-inducing stimulus up/downregulates Ih (Fan et al; Brager et al; SfN 2005), this suggests that LTP/LTD-inducing stimulus brings about an increase/decrease in θ. Observing this to match the requirement on θ within the BCM framework, we propose Ih as a candidate mechanism for regulating θ. Next, we show that an increase in the conductance of (i) AMPAR/NMDA...