  We have developed a linearization method to investigate the subthreshold
oscillatory behaviors in nonlinear autonomous systems. By considering firstly
the neuronal system as an example, we show that this theoretical approach can
predict quantitatively the subthreshold oscillatory activities, including the
damping coefficients and the oscillatory frequencies which are in good
agreement with those observed in experiments. Then we generalize the
linearization method to an arbitrary autonomous nonlinear system. The detailed
extension of this theoretical approach is also presented and further discussed.
