Abstract: Spikefrequency adaption is a prominent feature of neuronal dynamics. It plays an important role in neuronal information processing. To investigate the different mechanisms of spikefrequency， two kinds of modified leaky integrateandfire models(LIF models)under external alternating electric field were established. The curves of the onset spike frequency and the spikefrequency of the steady state were analyzed. The LIFAC shifted the frequency curves to higher inputs without affecting its slope， and the LIFDT had a divisive effect on the frequency curves. The spike frequency of the steady state was linear under the external alternating electric field. The effects of external alternating electric field on different kinds of adaption mechanisms were also analyzed by the correlation and the variability between consecutive interspike intervals.

Key words: spikefrequency adaption, external alternating electric field, leaky integrateandfire(LIF)neuron model, LIFAC and LIFDT firing mechanisms, correlation