A modified Hodgkin-Huxley model
It is a biological modeling assignment to be written using the Xppaut software. There will need to be postscript graphs. 1) A modified Hodgkin-Huxley model One considers a neuron model where voltage evolution is given by C ddVt = Gl(Vl - V ) + GNam8(V )3h(ENa - V ) + GKn(EK - V ) + I Sodium current activation is assumed to be instantaneous m and the gating variables h and n satisfy the equations th ddht = h8(V ) - h and tn ddnt = n8(V ) - n where th and tn are both equal to 1 ms, h n Other parameters are C = 0.8nF, Gl = 0.3µS, GNa = 40µS, GK = 3.5µS, Vl = - 66mV, ENa = 50mV, EK = - 90mV. Draw the voltage response of the model to a constant injected current for several values of this current. Draw the bifurcation parameter using the injected current as the bifurcation parameter. Interpret the results. 2) Effect of an AHP current One adds to the model a afterhyperpolarization (AHP) current IAHP = GAHPz(EK - V ) where GAHP = 0.3µS. The gating variable z satisfies tz(V ) ddzt = z8(V ) - z ...