  This paper presents a modified Morris-Lecar model by incorporating the sodium
inward current. The dynamical behaviour of the model in response to key
parameters is investigated. The model exhibits various excitability properties
as the values of parameters are varied. We have examined the effects of changes
in maximum ion conductances and external current on the dynamics of the
membrane potential. A detailed numerical bifurcation analysis is conducted. The
bifurcation structures obtained in this study are not present in existing
bifurcation studies of original Morris-Lecar model. The results in this study
provides the interpretation of electrical activity in excitable cells and a
platform for further study.
